CN111093742B

CN111093742B - Method and apparatus for treating and delivering fluid to an eye

Info

Publication number: CN111093742B
Application number: CN201880052007.4A
Authority: CN
Inventors: M·纽威尔; L·克劳斯; N·路易斯; M·雷伊
Original assignee: Corinthian Ophthalmic Inc
Current assignee: Corinthian Ophthalmic Inc
Priority date: 2017-06-10
Filing date: 2018-06-11
Publication date: 2022-09-16
Anticipated expiration: 2038-06-11
Also published as: US11938056B2; JP7227163B2; KR20200019172A; US20200197218A1; AU2018279940A1; IL271229A; WO2018227190A1; CN111093742A; US12213912B2; US20250248842A1; JP2023053118A; CA3066408A1; US20240285430A1; KR102643190B1; AU2018279940B2; EP3634550A1; SG11201911895XA; KR102782406B1; CN115300226A; EP3634550A4

Abstract

Methods and apparatus for handling and delivering fluids to the eye. The device has a vibrating element having a plurality of openings through which fluid is ejected when vibrated. The housing defines a chamber containing a single application of fluid. The housing may be biased against the vibrating element by a spring load generated in whole or in part by the elastic structure of the housing. After a single application, the chamber may be substantially empty.

Description

Method and apparatus for treating and delivering fluid to the eye

Technical Field

The present invention relates to methods and apparatus for treating and delivering fluids to the eye.

Background

The delivery of fluids to the eye presents a number of challenges. The fluid should be provided with a controllable droplet size and delivered at a controllable rate to achieve comfort, while being delivered at a sufficiently high rate to deliver the entire dose. Another challenge with fluid delivery to the eye is the need for rapid delivery so that blinking does not interfere with delivery.

Fluid delivery devices for the eye have used piezoelectric elements to vibrate an element, such as a plate, that has an orifice through which fluid is ejected. A problem with many of these devices is that they are typically "wet" systems in which the fluid is exposed through holes in the plate during storage, which can lead to undesirable evaporation and contamination between uses.

Disclosure of Invention

The present invention relates to methods and apparatus for treating and delivering fluids to the eye. In one aspect, the fluid to be delivered to the eye is contained in a housing that retains the fluid to be dispensed within a chamber defined by the housing. The housing maintains a dose of fluid in the vicinity of the opening so that the fluid can be ejected in a short time with little residual volume remaining.

The housing has a lip located adjacent the vibratory element having an opening through which fluid is ejected. The lip may not be attached to the vibrating element but may be in contact with the vibrating element or may be spaced a small distance apart so that surface tension keeps the fluid within the chamber. The vibrating element may have a smaller maximum amplitude of vibration when vibrating, which is less than the average separation distance between the lip and the vibrating element or less than the minimum separation distance between the lip and the vibrating element.

The housing may also be shaped to cooperate with the vibratory element to avoid capillary feed near the opening in the vibratory element. To this end, the housing may be spaced from the vibratory element such that at least 75%, at least 95%, or all of the openings are spaced from the proximal-most portion of the housing by at least 0.014. Capillary feed may be incorporated into other aspects of the invention without departing from those aspects of the invention. The shape of the housing also allows all the fluid to reach the opening in a short time. The housing has an inner surface in contact with the fluid shaped such that at least 75%, at least 95%, or even all of the inner surface is no more than 0.060 inches or no more than 0.040 inches from a nearest opening of the plurality of openings. In other words, the inner surface of the housing is shaped such that the chamber is formed such that at least 75%, at least 95% or all of the inner surface has a direct line of sight to the at least one opening. The inner surface of the housing may be hydrophobic over at least 70% of the inner surface in contact with the fluid.

The lip may be biased against the vibrating element with a moderate force to prevent fluid from escaping, while not excessively dampening the vibration. The lip may exert a force on the vibratory element of no greater than 3 grams-force, as measured in the direction of the central axis of the vibratory element. The lip may also apply a spring load to the vibrating element so that it can accommodate small displacements due to temperature, pressure or impact from an impact (drop). The spring load may also help account for manufacturing tolerances that may affect the load applied to the vibratory element by the lip. The lip portion may exert a spring load on the vibration element with an average spring constant of not more than 60 grams force/millimeter with a displacement of not more than 0.050 mm. The housing itself may be resilient, with the walls of the housing having a tapered portion with thinner walls to provide flexibility. The tapered portion of the wall has a ratio of radial displacement to longitudinal displacement of at least 1 to 3, at least 1 to 2 and may be at least 1 to 1. In other words, the tapered portion also extends radially relative to the open end of the housing by at least half of the effective radius of the open end of the housing. The lip and/or the vibrating element may have a PTFE coating adjacent to one another to reduce friction therebetween. The coating may extend around at least 270 degrees when viewed along the central axis.

The housing may allow air to enter through the opening and/or between the lip and the vibratory element in place of the jetted fluid, and may not include a dedicated vent. The maximum amplitude may be slightly less, which allows air to enter the chamber while still preventing fluid from escaping from the chamber. The shell-to-vibrating element interface defines an enclosed boundary (which may be defined by the vibrating element or the shell) that extends radially outward at least 0.3 times the effective radius of the enclosed feed region beyond the additional area of the opening.

The housing may include a wall opening through the wall that exposes the chamber through the wall. A wall opening extends through the wall to expose the chamber through the wall without allowing fluid to escape, while allowing air to enter when the fluid is ejected. The wall opening has a longitudinal dimension measured from the lip in a direction of the central axis and a radial dimension measured in a radial direction relative to the central axis. The housing also has an inner wall, the side of which faces the opening in the vibrating element. The longitudinal dimension of the wall opening is at least 80% of the separation distance between the vibrating element and the side of the housing facing the opening. The radial dimension of the wall opening may be no greater than 10% or no greater than 5% of the equivalent circumference of the lip.

The wall opening tapers as it extends proximally away from the lip. The wall opening extends proximally from the lip, and a circumferential dimension of the wall opening gradually decreases as the wall opening extends proximally from the lip. The wall opening is tapered such that the tapered shape is oriented in a direction of the fluid inlet toward the chamber when viewed along the central axis. The wall opening may also extend through the frustoconical portion of the wall, and may extend proximally from the lip for at least 80% of the length of the frustoconical portion.

The fluid may be rapidly delivered at a relatively high velocity and pressure to encourage all of the fluid to accumulate within the chamber. The total downstream volume of the fluid path from the pump or valve of the isolation chamber may be of a magnitude greater than the volume that allows the fluid to move slightly within the housing and coalesce into a single droplet due to surface tension. The volume of fluid may be 40% to 70% of the total downstream volume.

The housing may also divide the fluid flow into at least two (and may be three, four or more) inlets of the chamber. Each inlet directs fluid to the sidewall before directing fluid to the plurality of openings. The housing has a main inlet that directs flow in a direction within 30 degrees of the central axis, and an inlet to the chamber that is 60-90 degrees from the central axis and directed toward the sidewall. The housing may be an integrally formed structure defining the chamber.

The pump may have a first portion and a second portion that reciprocate in a single cycle from a storage position to a forward stroke position and back to the storage position. A cavity is formed between the two parts, in which cavity the fluid is sucked and subsequently discharged into the chamber. The air replenishment chamber may also be coupled to a pump to force air into the fluid container during each cycle to actively vent the fluid container.

The invention may be embodied as an apparatus or as a method. With respect to the device, it should be understood that the treatment delivery device can be divided into reusable and disposable portions in myriad different combinations. Thus, the present invention provides inventive concepts that may be logically grouped together in various ways that define subsets of devices, which may be disposable or reusable portions. For example, the fluid container may be replaced with a housing, or may be self-contained and therefore may be claimed in any manner. The housing may form part of a reusable device with the vibrating element or may be a disposable part (with or without a fluid container) without departing from the scope of the invention. The claimed invention resides in the methods and structures rather than in the specific description of the disposable and reusable components. It is therefore to be understood that the disposable component may be defined in any suitable manner, and the claims may define any such limited aspect or combination. As a further example, the claims may define the pump and the fluid container, the housing and the vibrating element, or even a single structure, such as the housing itself. Each of these devices may be a reusable device, a disposable device, or a portion of a disposable device, and may therefore be claimed.

These and other features will become apparent from the following description of the preferred embodiments, the claims and the accompanying drawings.

Drawings

Fig. 1 shows an apparatus for treating and delivering fluids to the eye with the cap removed for introduction into the fluid container.

Fig. 2 shows a vibrating element with an opening through which a fluid is ejected.

Fig. 3 illustrates a locking mechanism for a fluid container.

FIG. 4 shows the first housing portion with the outer cover removed to show the gate having an aperture through which fluid is dispensed.

Fig. 5 shows a cross section of a second housing part accommodating the control system and the battery.

Fig. 6 shows a front view of the device with the outer cover removed.

Fig. 7 illustrates a fluid delivery path from a fluid container to a housing.

Fig. 8 shows a cross-section of the housing.

Fig. 9 shows another cross-section of the housing.

Fig. 10 shows a perspective view of the housing.

Fig. 11 shows a bottom view of the housing including the diverter chamber.

Fig. 12 shows an enlarged cross-sectional view of the housing.

Figure 13 shows a cross-sectional view of the device in a storage position.

Fig. 14 shows the pump with the fluid contained therein advancing during the forward stroke.

Fig. 15 shows the pump in a full forward stroke.

Figure 16 shows the pump at the end of the fluid delivery through the conduit into the housing.

Fig. 17 shows the pump during the return stroke.

Fig. 18 shows a front view of the shutter in the storage position.

Fig. 19 shows a front view of the shutter in the ready position.

Figure 20 shows a rear view of the apparatus with the pump in the storage position.

Fig. 21 shows a rear view of the apparatus with the pump in a forward omni-directional stroke position.

Figure 22 shows a perspective view of the apparatus with the return spring of the pump removed.

Fig. 23 shows a perspective view with the cover and outer cover removed.

Fig. 24 shows a perspective cut-away view of the fluid delivery path and the shutter.

Fig. 25 shows the ram mechanism and firing button in the storage position.

Fig. 26 shows the shutter in a ready state, in which the shutter spring is loaded.

Fig. 27 illustrates actuation of the firing button to release the shutter.

Fig. 28 shows the shutter being moved upward by the pump spring at the end of fluid delivery.

Fig. 29 shows a partial cross section of the apparatus, showing the shutter mechanism.

Fig. 30 shows a perspective view of fig. 29.

FIG. 31 shows the rams in a ready state and the sensors that prevent the delivery of fluid when the rams prevent the delivery of fluid.

Fig. 32 shows a plan view of another housing with a wedge-shaped wall opening.

Fig. 33 is a perspective view of the housing of fig. 32.

Fig. 34 is a side view of the housing of fig. 32-33.

Fig. 35 is a cross-sectional view of the housing of fig. 34.

Detailed Description

The present invention relates to methods and apparatus for treating and delivering fluids to the eye. Referring to fig. 1, 2 and 7, an apparatus 1 is shown comprising a fluid ejector 2 (fig. 2) and a fluid processor 14 (fig. 7). The fluid ejector 2 includes a vibrating element 4 having a plurality of openings 6, the openings 6 being vibrated by a piezoelectric element 15 coupled to the vibrating element 4. The term fluid as used herein refers to any flowable substance and not just to the liquid state of a material.

The device 1 has a housing 5, which housing 5 may comprise a first housing part 7 and a second housing part 9, which are locked together by any suitable engagement, such as a twist or snap fit. Referring to fig. 5, a control system 11 including a printed circuit board 13 is mounted to the first housing portion 7. The control system 11 is coupled to the piezoelectric element 15 and controls the piezoelectric element 15 as is known in the art. As is known in the art, the battery 19 powers the control system 13 and the drive electronics of the piezoelectric element 15. A fluid handling system 14 is coupled to the second housing portion 9. The control system 11 may be reusable while the fluid processor 14 may be disposable. Furthermore, the fluid may be held in a fluid container 17, which may be locked to the first housing 7 to prevent removal, so that the fluid processor 14 is disposable after (having) the first fluid container 17. Of course, the fluid handling system 14 may also be used with more than one container 17, or the container 17 may have a reservoir that is filled without departing from many aspects of the present invention. Further, the entire system 1 may be disposable or reusable, or may be divided into disposable and reusable portions in a variety of ways without departing from most aspects of the present invention.

The piezoelectric element 15 may be an annular disk 23 coupled to the delivery side 8 or the fluid side 10 of the vibratory element 4, wherein the opening 6 is located in an open central region 26 of the annular disk 23. The piezoelectric element 15 may be made of any suitable material (e.g., lead zirconate titanate, chemical formula Pb [ Zr ] _x Ti _1-x ]O ₃ An intermetallic inorganic compound of (a). The piezoelectric element 15 may be bonded, adhered, molded or otherwise coupled to the vibratory element in any suitable manner known in the art. The flex circuit 21 is in electrical communication with the piezoelectric element 15 to control the piezoelectric element 15. The flexible circuit 21 is coupled to the control system 1 (see fig. 5), and the control system 1 controls the piezoelectric element 15 to induce vibrations in the piezoelectric element, thereby vibrating the element 4 and ejecting fluid from the opening 6. The vibrating element 4 vibrates at a frequency of 100 to 160kHz, which may be a resonance frequency. The resonant frequency may be predetermined, measured, determined or tuned, as is known in the art. The driving frequency of the piezoelectric element 15 is further described below. Of course, the operating frequency may be a frequency other than the resonant frequency.

At the opening 6, the fluid side 10 of the vibrating element 4 is in contact with the fluid to be delivered and ejects the fluid to the delivery side 8. When the vibrating element 4 vibrates, the fluid is ejected toward the eye through the opening 6. The opening 6 may taper from the fluid side 10 to the delivery side 8. For example, the opening 6 at the fluid side may have a diameter of 160-240 microns (and may be 200 microns), while the diameter at the delivery side may be 20-60 microns (and may be 40 microns). A cylinder of uniform diameter (20-60 microns) extends to the delivery side 8 and is 10-40 microns long and may be about 25 microns long. The opening 6 may have a curved wall with a radius of curvature of 100 micrometer between the fluid side and the delivery side. The openings 6 at the fluid side 10 and the delivery side 8 may have a circular cross-sectional shape. As used herein, the cross-sectional area (or other dimension) may be defined by the effective diameter (or effective radius) of a circle having the same area.

The vibrating element 4 may have a thickness of 100 to 180 microns or 120-160 microns and may be about 140 microns and may be made of any suitable material such as PEEK or polyimide with additional layers of copper, polyimide, nickel and/or gold. The vibrating element 4 may have a thickness of 125 microns and the coating/plating has a total thickness of about 15 microns, such that the vibrating element 4 has a thickness of about 140 microns. Of course, many other configurations may be practiced within the scope of the present invention, with respect to the materials and fabrication of the vibrating element 4 and piezoelectric element 15, and the size of the opening 6.

The fluid may be sprayed such that its average spray velocity on the delivery side 8 as it leaves the opening 6 is between 2.5m/s and 15m/s, and may be about 5-6 m/s. The vibrating element 4 defines a central axis CA, which is the central orientation of the plurality of openings 6 defined by the geometric center of the ejection orientation of the plurality of openings 6. For a circular pattern of openings 6 with a uniform density distribution of flat vibrating elements 4, the central axis CA extends perpendicular to the plane of the vibrating elements 4 at the center of the circular pattern of openings 6. In other words, the central axis CA is perpendicular to the plane defined by the vibrating element 4 and is aligned with the geometric center of the ejection direction in which the openings 6 are aligned or with the geometric center of the ejection pattern formed by the plurality of openings 6. The central axis CA may be defined by an average or geometric center, for example, when the openings 6 as used herein are clustered or irregularly shaped or asymmetrically shaped or the density of the openings 6 (number of openings)/mm 2 varies, without departing from the scope of the invention.

Referring to fig. 1, 3 and 7, multiple doses of fluid are stored in the fluid container 17, and the fluid container 17 is locked to the housing 5 (particularly the second portion 9) when the notch 22 engages the locking tab 24 on the container lock 26. The snap-fit connector 28 (fig. 3) locks to a manifold 30 (fig. 7) of a pump 32, as described below. When the container 17 is pushed down and locked to the housing 5, the fluid delivery needle 34 passes through a pierceable element 36, such as a septum 38, in the container 17. Vent needle 40 may be disposed independently or concentrically with fluid delivery needle 34 and also pass through pierceable member 36. As further explained below, fluid is drawn from the container 17 through the fluid conduit 42 by the pump 32. Air is drawn into an air intake chamber 27 (covered by a filter 29) which, as described below, is used to ventilate the container 17.

Referring to fig. 7-12, individual doses of fluid are delivered to the chamber 16 formed by the housing 18 and the vibrating element 4. The chamber 16 may be substantially dry after delivery of the fluid and dry when stored, which may provide advantages over "wet" systems that may suffer from unwanted contamination or evaporation. The housing 18 has a wall 44 with a lip 46 located near the fluid side of the vibrating element 4. The lip 46 extends around the plurality of openings 6. The housing 18 and the vibratory element 4 together define the chamber 16, or the chamber 16 may be defined by the housing 18, with the housing 18 being bounded by the open end 33 of the housing 18, and the open end 33 being bounded and defined by the lip 46. Wall 44 extends from open end 33 to a hub 35 having a main inlet 52. The primary inlet 52 is coupled to a lumen 54 formed in a tube 56 through which fluid is delivered by the pump 32. The passage housing 18 may be formed with the tube 56 or as a separate part as shown. The tube 56 may be formed with the manifold 30, and the manifold 30 may be defined as part of the pump 32 such that the pump 32 delivers fluid directly to the housing 18. The manifold 30 has mounting ribs 31 (fig. 22) that engage the housing. As used herein, the tube 56 may also be defined separately from the pump 32, for example, the tube 56 may be part of the housing 18 (either as a disposable part or a reusable part).

The lip 46 of the housing 18 is positioned adjacent the fluid side 10 of the vibratory element 4 to prevent fluid from escaping or leaking between the lip 46 and the vibratory element 4. The lip 46 and vibrating element 4 are adjacent to each other along a closed loop around the opening 6, which is 0.190-0.240 inches in diameter, and may be 0.210 inches. The outer shell 18 also defines a central axis CA that is the geometric center of the area bounded by the lip 46 at the open end of the outer shell 18 and is oriented perpendicular to the area bounded by the lip 46. The term central axis CA as used herein may refer to any definition applicable herein and may be interchangeable as applicable, and such substitution is expressly included wherever the term central axis CA is used (e.g., when the two are collinear). Of course, the central axis CA of the housing 18 and the central axis CA of the vibratory element 4 may be offset and/or skewed and in particular independent definitions apply without departing from the scope of the invention as described below.

The lip 46 of the housing 18 may be spaced from the vibratory element 4 such that the lip 46 does not impede vibration of the vibratory element 4. Of course, the lip 46 must be close to the vibrating element 4 so that surface tension prevents the liquid from escaping. For example, the lip 46 may be spaced from the vibratory element 4 by less than 250 microns or less than 125 microns. When the maximum amplitude is small enough to prevent contact, the vibrating element 4 does not contact the housing 18 during vibration. In other words, lip 46 has a surface that is spaced from vibrating element 4 by less than 250 microns on average or less than 125 microns on average, and is spaced from vibrating element 4 by an overall angular extent of at least 270 degrees that does not contact vibrating element 4. In other words, the surfaces are spaced apart by a separation distance of at least 125 microns around at least 270 degrees of the plurality of openings 6 when viewed along the central axis CA. The lip 46 may extend completely around the opening 6 without contacting the vibratory element 4 even during vibration for fluid transport. The interface on either side may be interrupted rather than continuous without departing from the scope of the invention. For example, the surface of the lip 46 may contact the vibrating element 4 along four small segments, each spanning 20 degrees, so that the lip 46, if not continuous, does not contact the vibrating element 4 along at least 270 degrees. As used herein, the chamber 16 is defined by the housing 18 and the vibrating element 4 as long as fluid is prevented from escaping between the housing 18 and the vibrating element 4, and the chamber 16 should be defined as a fluid holding space even if the chamber 16 is not completely surrounded. As used herein, the term "lip" refers only to the surface adjacent to the vibrating element 4 and does not require any particular structure or shape, and may be only the end of the wall 44 or a coating at the end of the wall 44. The lip 46 may be wider, such as a flange, an edge of a rigid cup or a corrugated surface, an undulating or serrated surface, without departing from the meaning of "lip" as used herein. Although fluid may be retained in the chamber 16 by surface tension along the lip 46 when the lip 46 is spaced from the vibratory element 4, most fluids may not have capillary feed features, as is sometimes used in the prior art. Such prior art systems incorporating capillary feed typically do so along a fluid feed area proximate to the opening 6 in the vibratory element 4. As described below, the present invention may provide sufficient space adjacent to the opening 6 such that capillary action is not required or involved to deliver fluid to the opening 6.

The lip 46 may also be in contact with the vibrating element 4, rather than spaced apart, while not over-constraining the vibrating element 4 and still retaining fluid. For this reason, the lip 46 may be biased against the vibration element 4 with a small force. For example, the force exerted by the lip 46 on the vibrating element 4 may be less than 3 grams-force, and may be less than 2 grams-force, measured in the direction of the central axis CA of the housing 18 (and the vibrating element 4). The lip 46 may also exert a controlled spring load on the vibratory element 4 with an average spring constant of no greater than 60 grams force/millimeter, or even no greater than 40 grams force/millimeter for displacements up to 0.050 millimeters in the direction of the central axis CA. The controlled spring constant may aid operation under extreme conditions for extreme temperatures, pressures and shock loads (drop) that may affect the interaction of the lip 46 and the vibratory element 4. The controlled spring constant may also aid manufacturability as manufacturing tolerances may affect the load ultimately exerted on the vibrating element 4 by the lip 46.

The lip 46 and/or the wall 44 may also be made of a resilient material for compliant contact between the lip 46 and the vibratory element 4, and the resilient material and geometry of the housing 18 may contribute to the resilient response. For example, the lip 46 may be made of a material having a hardness of less than 60A. The wall 44 may have a thickness of 0.003 to 0.007 inches around the chamber 16. The resiliency of the housing 18 may be provided by the material of the lip 46 itself and/or mechanically by tabs, leaf springs, coil springs, cantilevers, resilient brackets for the container 17, or any other suitable mechanism or combination. For example, in accordance with this aspect of the invention, the housing 18 may be a rigid cup with an elastomeric coating along the rim, with a suitable spring exerting a force on the cup.

The wall 44 of the housing 18 includes side walls 56, the side walls 56 also contributing to and in some cases maximizing the resiliency of the engagement with the vibratory element 4. The side wall 56 extends from the lip 46 to the hub 35 and extends completely around the central axis CA. The resiliency of the housing 18 may be provided in whole or in part by the shape of the side walls 56. The sidewall 56 may have a tapered portion 60 extending from a large end (0.210 to 0.220 inches in diameter) to a small end (0.180 to 0.190 inches in diameter), with the large end positioned closer to the vibrating element 4 (and may be adjacent the lip 46 at the distal end) and surrounding and containing a larger area than the small end. The tapered portion 60 of the sidewall 56 may also include a first frustoconical portion 62 extending from the lip 46 and a radial extension 64 extending primarily radially inward from a small end of the first frustoconical portion 62 to the hub 35. The radially extending portion 64 extends radially inward relative to the center axis CA of the housing 18. The orientation and relative dimensions of the portions of the wall 44 and the sidewall 56, when viewed along the central axis CA (or completely around the central axis CA as shown), are described herein with reference to the cross-sectional shape at the plane of the central axis CA (of the vibratory element 4 and/or the housing 18) for a total angular range of at least 270 degrees. The radial extension 64 extends radially inward at least 20% of the equivalent radius of the open end. The radial extension 64 can have a ratio of radial to longitudinal displacement of at least 3 to 1 relative to the central axis CA, wherein the central axis CA represents the longitudinal direction and can be positioned 0.014 to 0.030 inches or 0.014 to 0.040 inches from the vibratory element 4 as measured along the central axis CA. As used herein, "equivalent radius" or "equivalent diameter" refers to the radius or diameter of a circle having the same area. The tapered portion 60 of the sidewall 56 has a second frustoconical portion 63 that extends from a radially extending portion 64 to the hub 35.

The tapered portion 60 of the sidewall 56 extends from the lip 46 to the hub 35. In general, the tapered portion 60 may have a radial to longitudinal displacement ratio of at least 1 to 3, at least 2 to 3, or at least 1 to 1, relative to the central axis CA. As used herein, "taper" does not require a gradual or continuous change, but merely refers to a reduction in size perpendicular to the central axis CA representing the feed area. The reduction may be stepped or may extend substantially only radially inwardly like the radial extension 64 without departing from the definition of "tapered" as used herein. The tapered portion 60 of the sidewall 56 may extend radially (relative to the central axis CA of the outer shell 18) at least 20% of the effective radius of the surrounding boundary of the lip 46, at least about 270 degrees of the outer shell 18 (and may completely and completely surround the central axis CA) when viewed along the central axis CA. The tapered portion 60 of the sidewall 56 may have a thickness of 0.003 to 0.007 inches and may be about 0.005 inches to enhance the flexibility of the sidewall 56. The side wall 56 extends to the hub 35 and forms a connector 66 that engages the end of the tube 56 (fig. 7) having a mating connector (not shown). The main inlet 52 is formed by a hub 35, the hub 35 receiving fluid from a lumen 54 in a tube 56. The other end of the lumen 54 in the tube 56 receives fluid from the pump 32.

The lip 46 may not be attached to the vibratory element 4 while still in contact with the vibratory element 4. As used herein, the terms "unattached," "unattached," or "unattached" mean that there is no connection other than frictional contact. In other words, the lip 46 can freely move away from the vibrating element 4 along the central axis CA. Put another way, the housing 18 (and in particular the lip 46) is unattached and has a degree of freedom in the direction of the central axis CA relative to the vibratory element 4. Thus, the lip 46 and the vibratory element 4 may have channels and/or raised baffles or walls that may limit lateral movement, without constituting an "attachment" as defined herein. The lip 46 may have a curved surface with a radius of curvature of about 0.005 inches to provide the lip 46 with a rounded edge.

The vibrating element 4 and the lip 46 define an enclosed boundary 41 at the interface of the two (while each may define an enclosed boundary 41 as they define the same boundary as each other). The surrounding boundary 41 defines a surrounding feed area 51 (fig. 11) at the fluid side of the vibrating element 4, which may be 5.3-5.7mm or about 5.5mm in diameter. The opening 6 in the vibrating element 4 surrounds and defines a conveying area 39 of the vibrating element 4, which conveying area 39 is circular and has a diameter of 2.6 to 3.0mm or less than 3.0mm or about 2.8 mm. Of course, other patterns and shapes than circles may be used for comparison with the effective diameter or radius. The enclosing boundary 41 may be significantly larger than the conveying area 39, since the conveying area 39 may be no more than 75% or no more than 50% of the enclosing feed area 51. In other words, the enclosed feed area 51 may be at least 30% larger than the transport area 39, and may be at least 100% larger than the transport area 39. In other words, the enclosed feed area 51 may be larger than the conveying area 39, such that the overfeed area 58 (defined as the enclosed feed area 51 that is not coextensive with the conveying area 39 when viewed along the central axis CA) is at least 30% of the conveying area 39, and may even be larger than the conveying area 39, or even 50% larger. The overfeed zone 58 may be an annular ring for concentric arrangement, or may be crescent shaped for offset circular zones (which may be non-circular, but may be represented or likened to a circle when equal radii or diameters are used). The conveying area 39 of the vibrating element 4 defines the geometric centre and the effective radius of a circle of equivalent area. The surrounding feed area 51 also defines the geometric center and effective radius of a circle of equivalent area. The geometric center surrounding the feeding area 51 may be above the geometric center of the conveying area 39 and offset by at least 0.3 times the effective radius of the conveying area 39. The fluid held in the chamber 16 also defines a geometric center that is less than 0.015 inches from the vibrating element 4 as measured in the direction of the central axis CA. For offset designs, the geometric center of the fluid may be similarly positioned above the geometric center of the delivery region 39 at least 0.3 times the effective radius of the delivery region 39. For a concentric embodiment, the geometric center of the fluid (or volume of the chamber 16) is less than 0.1 times the effective radius of the delivery area 39 from the central axis CA of the vibrating element 4.

Although the housing 18 provides a smaller chamber 16 having a smaller volume, the chamber 16 may provide fluid to the opening 6 without the need for capillary feed as taught by some prior art. The housing 18 has an inner surface 49, the inner surface 49 defining the boundary of the chamber 16 defined by the housing 18. Fluid is held in the chamber 16 and in contact with the inner surface 49. The inner wall 45 of the housing 18 has sides that face the opening 6 and are spaced from the opening 6 by a spacing of about 0.017 inches. The spacing between the inner surface 49 of the housing 18 and the vibrating element 4 may be greater than the capillary spacing so that there is no capillary action. When rapid fluid delivery is desired, capillary feed can impede fluid flow and also make it difficult to fully deliver from the feed system, which presents residual fluid problems. To avoid possible capillary action and/or to minimize flow obstruction, it may be desirable to have a minimum separation between opening 6 and the nearest portion of housing 18 such that at least 75% or at least 95% or even all of opening 6 is at least 0.010 inches, or at least 0.014 inches, of the nearest portion of inner surface 49 of housing 18.

Although it may sometimes be desirable to avoid capillary action, it is still desirable to provide rapid transport of substantially all of the fluid, and therefore, housing 18 may still be shaped so that the fluid in chamber 16 does not need to travel far to reach opening 6 for ejection. To this end, the inner surface 49 of the housing 18 may be shaped such that at least 75%, or at least 95%, or even all of the fluid in direct fluid communication with the fluid in the chamber 16 is no more than 0.060 inches, or no more than 0.040 inches from the nearest opening 6 in the vibrating element 4. In other words, the chamber 16 may be shaped and formed by the inner surface 49 of the housing 18 such that at least 75%, 95%, or even all of the fluid in the chamber 16, and optionally all of the fluid in fluid communication with the fluid in the chamber 16, has a direct line of sight to the nearest opening 6. Many prior art systems have wet feed tubes or conduits filled with liquid and are much further away from the opening 6 than 0.060 inches and must overcome surface tension and other forces that may tend to retain the fluid in the conduit, which may result in a residual volume. Thus, in some instances, it may be desirable to have most, if not all, of the openings 6 separated from the housing 18 by a minimum distance to avoid capillary action while all of the fluid is still relatively close to the openings 6 without preventing rapid substantially complete delivery in a short period of time and with low residual volumes. When addressing both of these issues, the housing 18 forming the chamber 16 may be spaced 0.014 to 0.040 inches from all of the openings 6 as viewed and measured in the direction of the central axis CA of the vibrating element 4. Fluid "in fluid communication" with another fluid refers to a continuous fluid that includes feed tubes, conduits, wicks, and channels that deliver the fluid to the openings.

The housing 18 may be an integrally formed structure defining the chamber 16. The integrally formed structure may be made of a thermoplastic elastomer and may be formed by a suitable method such as injection molding. One example is the name supplied by Kraiburg as

TF5CGN of (1), which is a thermoplastic elastomer.

The volume of fluid delivered may fill only 75-90% of chamber 16, which may provide space during delivery to encourage all fluid to collect in chamber 16 due to surface tension. Delivering fluid to housing 18 at a velocity of at least 0.5m/s (or at least 1.0m/s) may also cause substantially all of the fluid ejected from tube 56 to collect in chamber 16 rather than being left in chamber 16 as a residue. In other words, the pump delivers fluid at a pressure of at least 200psi (and may be about 300psi) which may be sufficient to achieve the desired velocity for many fluids delivered to the eye. In this manner, a small amount of fluid remains as a single "droplet" of fluid that is ejected into the housing 18.

The housing 18 may divide the flow from the primary inlet 52 into a first inlet 55 and a second inlet 57, respectively, leading to the chamber 16. The housing 18 may also have a third inlet 59 and a fourth inlet 61, and when discussed separately, all aspects of the first and/or

second inlets

55, 57 are expressly incorporated into the third and/or

fourth inlets

59, 61 and the other of the first and

second inlets

55, 57, and all such features and limitations are expressly incorporated into all other inlets. The first inlet 55 directs the fluid at the inner surface 49 of the housing 18, e.g. the tapered portion 60 of the side wall 56, before being directed to the opening 6 in the vibrating element 4. The first inlet 55 and the second inlet 57 may open directly into the chamber 16, with both inlets being oriented to direct all of the fluid (or at least 90% of the fluid) entering the chamber 16 onto the inner surface 49 of the housing 18 (e.g., along the inner surface 49 of the side wall 56) before being directed to the opening 6 in the vibrating element 4. In this way, the likelihood of fluid being forced through the opening 6 during filling of the chamber 16 may be reduced. In particular, it would be advantageous to direct fluid into the housing 18 in this manner when the fluid is forced into the chamber 16 at a velocity or pressure as suggested herein.

The main inlet 52 first directs the fluid to the inner wall 45 opposite the opening 6 forming part of the diversion chamber 66. The inner wall 45 extends from one side of the side wall 56 to the other relative to the central axis CA to form an inlet. The flow splitting chamber 66 splits the flow into four flows that pass through four inlets, each inlet being spaced from and directed toward the tapered portion 60 of the sidewall 56. The diverter chamber 66 may open directly into the chamber 16 as shown, or may have additional baffles or flow altering features. The main inlet 52 directs fluid in a direction within 30 degrees of the central axis CA of the housing 18, and may be aligned with and along the central axis CA as shown. The first inlet 55 and the second inlet 57 may be oriented to direct fluid within 30 degrees perpendicular to the central axis CA to avoid fluid being directed to the opening 6. The housing 18 may have a third inlet and a fourth inlet that are also oriented at the side wall 56 of the housing 18. Adjacent inlets are also oriented 60-120 degrees from each other when viewed along the central axis CA of the housing 18, and may be at about 90 degrees from

adjacent inlets

55, 57, 59, 61, as shown.

The diverter chamber 66 has a cup-shaped wall 68 (which includes the inner wall 45), the cup-shaped wall 68 having a concave side 70 facing forwardly from the vibratory element 4. The cup-shaped wall 68 has all four inlets formed therein. The cup-shaped wall 68 extends radially outward from the central axis CA of the outer shell 18 at least 25% of an effective radius defined by the lip 46 for an angular range of at least 240 degrees relative to the central axis CA of the lip 46. The first inlet 55 has a radial dimension and a longitudinal dimension with respect to the central axis CA, and a ratio of the radial dimension to the longitudinal dimension is 0.5 to 1.5. When viewed in the direction of the central axis CA, the first inlet 55 and the second inlet 57 extend radially inwardly towards the central axis to expose some of the main inlets 52, but the guiding of longitudinal flow from the main inlets 52 towards the vibratory element 4 is prevented by a radial component of flow created by the bulk of the fluid being directed radially outwardly by the inner wall forming the bottom of the cup 68.

The chamber 16 is also formed such that at least two, three or four

inlets

55, 57, 59, 61 are provided which, together with the dimensions of the chamber 16, provide a lower energy state to encourage fluid to collect in the chamber 16 rather than leaving any residual portion of fluid in the separation chamber 66 or extending between the chamber 16 and the diverter chamber 66. While many aspects of the present invention are directed to minimizing residual fluid, the invention may be practiced with some residual volume retained, and indeed, certain aspects of the invention may be used with wet systems without departing from those aspects of the invention.

When fluid is evacuated from the chamber 16 (via the opening 6), make-up air must be introduced to vent the chamber 16 during operation. The housing 18 may vent air into the housing 18 between the lip 46 and the vibratory element 4, and the lip 46 is sufficiently separated from the vibratory element 4 during vibration to vent air into the housing 18 without releasing fluid. The air vented between the lip 46 and the vibratory element can assist in fluid transport by moving or displacing the fluid at the radially outer region radially inward toward the opening 6 and by simply occupying these radially outer spaces (excess feed space) rather than the remaining fluid that may occupy the space.

When fluid is ejected through the openings 6, air may also be drawn into some of the openings 6 of the vibrating element 4 to aerate the housing 18. Air is introduced in the form of small bubbles into the chamber 16 which can distribute the fluid to some extent to find the "active" ejection openings 6. The housing 18 may not include additional vents or dedicated vents, which simplifies the system and eliminates one possible contamination path or source. Of course, a dedicated vent could be provided for chamber 16 without departing from the present invention.

Referring to fig. 32-35, another chamber 16A and housing 18A are shown that are substantially identical to chamber 16 and housing 18, and all uses and combinations related to chamber 16 and housing 18 (and all other housings and chambers described herein) and all other disclosures are incorporated herein. Likewise, all discussion regarding chamber 16A and housing 18A is also included in chamber 16 and housing 18 (and all others). The housing 18A has a wall 44A with a lip 46A (see fig. 2) adjacent the vibratory element 4. Wall openings 124 are formed in the wall 44A to vent the chamber 16A during operation. The size of the wall opening 124 enhances the flexibility of the housing 18, as described below. The lip 46A may have a PTFE coating 120 adjacent the vibrating element 4 to reduce friction therebetween. The vibrating element 4 may similarly have a PTFE coating 122 adjacent the lip 46 to reduce friction therebetween. The

coatings

120, 122 may extend around at least 270 degrees when viewed along the central axis CA. Of course, the coating 122 may extend completely around the central axis CA. The inner surface 123 of the

housing

16, 16A may be hydrophobic (coated or by material properties) on at least 70% of the inner surface 123 of the housing 18A that is in contact with the fluid loaded prior to delivery.

The wall opening 124 may take any suitable shape, such as a wedge-shaped opening. Wall opening 124 extends through wall 44A, particularly a portion of sidewall 56A of wall 44A, to expose chamber 16A. The wall opening 124 may also form a small gap 131 in the lip 46A that, along with the geometry of the opening 124, is small enough to prevent fluid leakage, but may still be large enough to vent the housing 18A by allowing air to enter as the fluid is expelled. All discussions and applications relating to the venting of the housing 18 are included herein, such as the discussion of venting between the lip 14 and the vibratory element 4, the spacing between the lip and the vibratory element, and the force-displacement characteristics. Thus, lip 14A may be in contact with vibrating element 4 or spaced in any manner described herein.

The wall opening 124 has a longitudinal dimension 126 measured from the lip 46 in the direction of the central axis CA and a radial dimension 128 measured in a radial direction relative to the central axis CA. The longitudinal dimension 126 of the wall opening 124 is at least 80% of the spacing 125 between the vibrating element 4 and the side 47A of the housing 18A facing the opening 6, and may extend over substantially the entire length as shown. The radial dimension 128 of the wall opening 124 is no greater than 10% or 5% of the equivalent circumference of the lip 46A. The radial dimension 128 may be about 0.025 inches and the longitudinal dimension 126 may be about 0.022 inches. The dimensions of housing 18A, wall 124A, and chamber 16A may be any suitable dimensions, including dimensions associated with housing 18 and all geometric relationships, all of which are incorporated herein.

The wall opening 124 extends proximally from the lip 46A and, due to its location and shape, may increase the flexibility of the housing 18A. The wall opening 124 has a circumferential dimension 130 measured circumferentially relative to the central axis CA. The circumferential dimension 130 may be about 0.012 inches (as with the gap 131) at the lip 46A and tapered such that the sides converge at the proximal end 132 of the wall opening 124. The circumferential dimension 130 is defined herein as a measurement of a line segment in a radial direction perpendicular to the central axis CA. The wall opening 124 tapers as the wall opening 124 extends proximally from the lip 46A. The wall opening 124 is tapered such that the tapered shape 132 of the wall opening 124 is oriented in a direction ("pointing") to at least one of the

inlets

55, 57, 59, 61 of the chamber and may be oriented to align with both inlets when viewed along the central axis CA. Orienting the tapered shape 132 of the wall opening 124 with the

inlets

55, 57 in this manner increases flexibility because the inlets and the wall opening 124 cooperate to increase flexibility in geometric alignment. The "orientation" of the tapered opening should be defined as the bisection of the taper angle extending from the wall opening 124. The tapered shape 132 is also within 10 degrees of the radial direction relative to the central axis CA, and may be substantially radially oriented, as shown. The wall opening 124 is also located along the frustoconical portion 62A, with the wall opening extending proximally from the lip for at least 80% of the length of the frustoconical portion 62A.

The pump 32 will now be described in more detail. The pump 32 draws discrete volumes from the fluid container 17 and delivers these volumes to the chamber 16. In some applications, the fluid container 17 may be any other suitable mechanism, such as a piston/plunger associated with the fluid container 17. For multi-dose devices, the fluid carrying capacity of the fluid container 17 may be at least 150 times the volume of the chamber 16 (or the volume of fluid delivered). The pump 32 may be configured to deliver the same (and optionally only) volume at a time. Of course, the variable displacement pump 32 may also be used without departing from virtually all aspects of the present invention.

The present invention may be used to provide a single dose delivery in substantially the entire dose delivered, whereby there is little residual fluid in the chamber 16. The vibrating element 4 may deliver fluid from the housing 18 such that the remaining fluid (from the previous fluid delivery) occupies no more than 5% or no more than 2% of the total volume of the chamber 16, or less than 1 microliter remaining. In other words, the vibratory element is operated to dispense substantially the entire volume of fluid in communication with the opening 6 such that no more than 5% or no more than 2% (or less than 1 microliter) of the volume of fluid remains in the chamber 16 after the fluid is ejected and a single actuation for the ejection of the fluid. In this manner, after a single application of fluid (single firing actuation), chamber 16 is substantially empty. An advantage of some aspects of the present invention over other fluid delivery systems is that chamber 16 receives a single dose that is almost completely delivered to substantially dry chamber 16 and leave no residual fluid between activations. Contamination and degradation of the fluid may be reduced as compared to "wet" systems in which the fluid is kept in contact with the vibrating element 4 or is not completely transported between uses.

Housing 18 may be sized such that housing 18 may be filled with a volume of fluid of at least 70-95% as described above, which may help the fluid to collect in chamber 16 as a single droplet. The chamber 16 may define a relatively small volume, for example less than 14 microliters or 10-14 microliters. The fluid volume may be 7-12 microliters or 10-12 microliters. The lumen 54 in the tube 56 delivers fluid to the housing 18 through the primary inlet 52, the primary inlet 52 being 0.040 to 0.060 inches in diameter and may be about 0.054 inches. The diameter of the diverter chamber 66 may be substantially matched to the main inlet 52 of about 0.054 inches. The tube 56 extends from the main inlet 52 and may have a volume of less than 2 microliters to further minimize residual fluid. The tube 56 may be part of the housing 18 and may be formed with the housing 18 rather than as a separate part.

In use, fluid delivery to the eye may also be relatively rapid to reduce the likelihood of interference by blinks during delivery. Fluid delivery may take less than 200 milliseconds, and may even take less than 150 milliseconds or even 100 milliseconds. The vibrating element 4 may also be operated with pauses between vibration cycles during a single actuation. For example, the vibrating element may be driven by the piezoelectric element 15 for a first operational period of about 26ms, with a pause of about 3.65ms, followed by a second operational period of about 26 ms. The vibrating element 4 may be driven by the piezoelectric element 15 with two pauses, wherein the piezoelectric element 15 is excited or activated for a first time period, a second time period and a third time period, the first time period and the second time period being separated by the first pause, and the second and third periods being separated by the second pause in the driving vibration of the vibrating element 4. The first and second pauses in the driving vibration may be 0.5ms to 4.0 ms. Each of the first time period, the second time period, and the third time period may be 20-40 milliseconds, and the total time of delivery may be less than 150 milliseconds, even less than 100 milliseconds, and may be about 85.3 milliseconds. Each of the first, second, and third oscillation periods may be further subdivided into an active period of about 816us and an inactive period of about 586us for the piezoelectric element 15. During the non-activation time, the vibration element 4 may continue to vibrate and eject the fluid although not being actively driven by the piezoelectric element 15, and similarly, the vibration element 4 may continue to eject the fluid during each pause in the activation of the piezoelectric element 15. A "pause" may be defined as a continuous deactivation of at least 2% of the total time, and the total pause time of the plurality of pauses is at least 6% of the total delivery time, and may be about 8.5% of the total delivery time. The definition of the inactive time differs from the pause in that the pause is at least 2% of the continuous time, whereas the inactive time is shorter and can be defined as a continuous time of 0.5-1.0% of the total transport time, the sum of the inactive time being at least 30% of the total transport time. In other words, the deactivation time is a continuous time of 2.0% to 2.5% of the first time period (and the second and third time periods), and the total deactivation time is at least 30% of the first time period. Of course, the delivery time is defined for the purpose of illustrating the invention, and the activation time and pattern may vary depending on the surface tension of the jetting fluid.

As described above, the frequency of the alternating signal for activating the piezoelectric element 15 and then causing the vibration element 4 to activate and vibrate is induced at the driving frequency of 100kHz to 160 kHz. Further, the frequency is selected by the control system 11 to be a random frequency centered at the drive frequency (from 100kHz to 160kHz) for each activation of the delivery of multiple activations during a single delivery, and may be randomized at least 20 times and may be at least 40 times. In other words, for a single firing actuation, the vibration frequency is changed (at least randomly centered on the drive frequency) on average at least 33 times, so that the drive frequency of the piezoelectric element 15 lasts no more than 3% of the delivery time (on average) before being changed. It is believed that the chaotic nature of the randomization of the drive signal may contribute to the ejection of fluid. The random nature may be provided by a predetermined set of random values applied to the central operating frequency or by random values uniquely generated by the control system 11.

The vibrating element 4 may also be designed to vibrate with a lower maximum amplitude. For example, the maximum amplitude of vibration of the vibrating element 4 may be less than 2 microns, less than 1.5 microns, or in the range of 0.5-1.5 microns, 0.8-1.2 microns, or may be about 0.8 microns. The maximum amplitude of the vibrating element 4 may also be small compared to the size of the opening 6 in the vibrating element 4. For example, the maximum amplitude may be not more than 5%, or not more than 3%, of the effective diameter of the cross-sectional shape of the opening 6 at the conveying side. For example, when the maximum amplitude is 1.0 micron and the average diameter of the opening 6 on the conveying side is 40 microns, the maximum amplitude is only 2.5% or about 2.5% of the average diameter of the ejected droplets. The maximum amplitude also represents a smaller quantity than the thickness, for example not more than 5.0% or even not more than 3.0% of the thickness of the vibrating element 4 (measured from the fluid side to the delivery side). As used herein, the transport thickness may be the average thickness of the area bounded by the opening 6. The low amplitude operation may also facilitate ventilation through the openings 6, since air may enter through some openings 6 with even low displacement. The low amplitude operation may also help maintain fluid control between the lip 46 and the vibratory element 4. When the lips 46 are spaced from the vibratory element 4, the lips 46 may be spaced apart an average distance greater than the maximum amplitude of the vibratory element 4 during vibration. In other words, the maximum amplitude is smaller than the average separation distance between the surface of the lip 46 and the vibrating element 4.

Referring to fig. 13-17, the housing is partially removed to expose the pump 32. The pump 32 delivers fluid from the fluid reservoir 17 to the chamber 16 through the lumen 54 in the tube 56 and through the primary inlet 52 (see fig. 12). The fluid container 17 may be any suitable container, such as a vial, ampoule, bag, pouch, or a fixed container that is filled without departing from the scope of the present invention. Similarly, the pump 32 may be any suitable mechanism for delivering fluid to the housing 18 without departing from aspects of the present invention. Fluid container 17 has a pierceable cap 70 that is pierced by delivery needle 34 and vent needle 40. Delivery needle 34 defines a portion of the delivery flow path and vent needle 40 defines a portion of the vent path. The delivery flow path extends to the pump 32 and from the pump 32 through the tube 56 and the primary inlet 52 into the chamber 16. Referring to fig. 3 and 13, delivery needle 34 and vent needle 40 are mounted to container support 70, on which container 17 is mounted. The container support 70 has a coupling 72 that engages the manifold 30. The vent lumen 73 includes a one-way valve 76, such as an umbrella valve 78, that allows air to enter the fluid container 17 to compensate for lost fluid volume, as described below.

The pump 32 has a first portion 80 and a second portion 82. The first part 80 reciprocates between a storage position (fig. 13) to a partial stroke position (fig. 14) and to a forward stroke position (fig. 15) at maximum displacement. The first portion 80 is returned to the storage position to complete the cycle of delivering a volume of fluid to the chamber. The second portion 82 also reciprocates between a storage position to a forward stroke position at maximum displacement and returns to the storage position at each cycle. The first portion 80 has an extension 84 extending from a body 86. The body 86 has an end 88 facing an end 90 of a body 89 of the second portion 82. Extension 84 on first portion 80 extends toward and interlocks with extension 85, extension 85 extending from main body 89 of second portion 82. By engagement of the

extensions

84, 85 and/or the

ends

88, 90 of the

bodies

86, 89 with one another, the first portion 80 is driven and in turn drives the second portion 82 through each cycle. A cavity 92 is formed between the first portion 80 and the second portion 82, the size of the cavity 92 varying as the first and

second portions

80, 82 move toward and away from each other. As the first and

second portions

80, 82 move away from each other, the size of the cavity 92 increases, which draws fluid into the cavity 92 during the forward stroke. As the first and

second portions

80, 82 move toward each other, the size of the cavity 92 decreases, which transfers fluid from the cavity 92 to the chamber 16 during the return stroke. The cavity 92 has a volume corresponding to the volume of fluid delivered, which may be 7-12 microliters.

During the forward stroke of the first portion 80, fluid is drawn into the cavity 92. The first and

second portions

80, 82 are movable from the storage position of fig. 13 to the partial forward stroke position of fig. 14 and finally to the full forward stroke position of fig. 15. The first and

second portions

80, 82 move to the full travel position, with the first portion 80 pulling the second portion 82 upward due to the interlocking

extensions

84, 85 engaging each other. In the full forward stroke position, the pump 32 is ready to deliver fluid through the tube 56 into the housing 18.

When the first and

second portions

80, 82 reach the partial stroke position of fig. 16 during the return stroke, fluid has been delivered from the cavity 92 to the chamber 16. The first and

second portions

80, 82 complete the cycle by moving to the partial reset position of fig. 17 and again to the full reset position of fig. 13. An additional optional step may be to purge any fluid remaining downstream of chamber 16 with a separate displacing medium. Tube 56, chamber 16, and diverter chamber 66 represent the total downstream volume that is substantially free of fluid prior to delivery of the fluid. The volume of fluid delivered by pump 32 may be 40-70% of the total downstream volume, such that tube 56 and diverter chamber 66 may be substantially empty when fluid has been delivered to chamber 16. As described above, fluid may be ejected at relatively high velocities of at least 0.5m/s (or pumped at pressures of at least 200 psi) to "shoot" droplets into chamber 16, which allows surface tension to collect and hold small amounts of liquid together.

The pump 32 may also deliver make-up air into the container 17 to compensate for the lost fluid volume. During the forward stroke, the pump 32 draws air into the refill chamber 94 and pushes air from the refill chamber 94 towards the fluid container 17, such that air enters and aerates the fluid container 17 during the return stroke. The first and

second portions

80, 82 each have opposite ends 97 opposite the

ends

88, 89 that face each other to form the cavity 92. At least one of the opposing ends 97 of the first and

second portions

80, 82 may form a portion of the supplemental chamber 94 (e.g., the opposing end 97 of the second portion 82) such that movement throughout the stroke will also draw air into the supplemental chamber 94 during the forward stroke and expel air during the return stroke. Air is forced through the one-way valve 76, through the vent needle 40 and into the container 17 to compensate for the lost (delivered) fluid volume. When the first and

second portions

80, 82 reach the fully reset position, supplemental air has been delivered and the pump 32 is again in the storage position, the first portion 80 of the pump 32 blocking the primary inlet 52 to the housing 18. The O-rings are used to seal the connections and spaces between the first and second portions and the manifold, and along the vent and fluid transfer paths.

Referring to fig. 4, 6 and 18-23 together, a drive mechanism for the pump 32 is shown. The drive mechanism includes a first actuator 94 (which may be a button 95) coupled to a first side 96 of a rod 98. When the button is moved downward, lever 98 rotates about pivot P in the direction of arrow A. The second side 100 of the lever 98 is coupled to a support plate 102 of the first portion 80 of the pump 32 such that the first portion 80 moves upwardly with the first side 96 of the lever 98 from the storage position of fig. 18 and 21 to the forward stroke position of fig. 19, 20 and 22, wherein fluid has been drawn into the cavity 92. The lever 98 may provide a mechanical advantage of about 11/6 due to the difference in lever arm lengths. Of course, a power system using the battery 19 may also be used to move the fluid without departing from other aspects. When the button 95 is depressed, the ratchet 104 prevents rearward movement until the desired downward displacement (full forward stroke) is reached, at which point the ratchet 104 is released to allow the return stroke.

During the forward stroke, the first actuator 94 (e.g., a push button) also loads the pump return spring 95 (and may load both pump springs 95). The loaded pump return spring 95 drives the pump 32 back to the default or storage position during the return stroke. The pump return spring 95 may act on the first actuator 94, a lever, as shown, or directly on a portion of the pump 32 itself, such as the first portion 80, as shown. The first actuator 94 (button 95) also returns to the storage position. In the storage position, the body of the first portion 80 blocks flow through the lumen 54 in the tube 56, while the body of the second portion 82 blocks the vent path and the fluid delivery path. In this sense, the pump 32 acts as the valve 104, and the present invention may be implemented with a dedicated valve that closes the lumen 54 to the tube 56 and the fluid moves in another manner without departing from aspects of the present invention.

Referring to fig. 25-31, the apparatus 1 further includes a shutter 105 having an aperture 107, through which aperture 107 fluid is delivered. The shutter 105 blocks and covers the vibrating element 4 in the storage position, and may function as an "off" switch (or define an "off" state) when the position of the shutter 105 (specifically, the circular area of the shutter 105) is detected using the position sensor 110. As the first actuator 94 moves through the forward stroke, the ram spring 109 is also loaded. Unlike the pump return spring 95, the shutter spring 109 is locked in the loaded position of fig. 26. A position sensor 110 (which may be an optical, electromagnetic, electrical, or mechanical sensor) determines when the shutter 105 is in the firing position, wherein the aperture 107 is aligned with the fluid opening 6. For example, the sensor 110 may be an optical sensor coupled to the control unit 11 (and the reusable second housing) that senses markings on the shutter. When the position sensor determines that the shutter 105 is blocking (or will soon block) fluid delivery, fluid ejection is prevented. Fluid is delivered upon actuation of the second actuator 106 (which may be a firing button or a dose button 108), and when the shutter 105 is in the position of fig. 26 and the device is ready to deliver fluid, the second actuator 106 is unlocked. In use as described below, when the hole in the shutter 105 is aligned with the opening 6 in the vibratory element 4, the firing button 108 mechanically releases the shutter 105 and the fluid injector is activated by the control system 11, as determined by the position sensor 110.

The movement of the shutter 105 will now be described in more detail. Referring to fig. 4, 18 and 23, shutter 105 is in the storage position. The shutter 105 is moved downward by the first actuator 94 so that the tab 109 slides downward in the slot 111 and locks in the ready state of fig. 19 and 26. When a dose is loaded, the device is now in the "on" state by activating a switch (not shown). During the ram-locked state, another sensor (not shown) may determine that the device is loaded with fluid and ready to dispense a dose. Activation and subsequent activation and deactivation of the dose button 108 is the mechanism to trigger and terminate the dose/ejection, based on the determination of the position of the shutter 105 by the position sensor 110. Of course, many other timed delivery methods may be used, and further, fluid may be delivered in a manner unrelated to the operation of the rams 105.

Shutter lock 115 is moved to the position of fig. 27 by firing button 108, thereby causing tab 109 on shutter 105 to move upwardly in release slot 117 having ramp 119. The firing button 108 is mounted to a resilient arm 121, the resilient arm 121 having a pair of hooks 123, the hooks 123 engaging the shutter lock 115 and partially pulling the shutter lock 115 back to the storage position due to the resiliency of the arm 121. A button return spring 125 (see fig. 17) is compressed when actuated and returns the button 108 to the ready state, and may also be used to return the ram lock 115 to the storage position.

The use of the apparatus for treating and delivering a dose of fluid will now be described. The fluid container 17 may be installed prior to use, or may be pre-loaded or loaded from a previous use. When the fluid container 17 is loaded a first (and optionally only one) time, the fluid container 17 is installed in the cavity 92 and the button is placed over the fluid container 17. The user then depresses first actuator 94 to force container 17 downward such that vent needle 40 and delivery needle 34 pierce the fluid container, as shown in fig. 7. The fluid container 17 may be locked to prevent removal and replacement of the fluid container 17. The device may be stored in this state.

Immediately prior to determining the delivered dose, fluid is delivered to the chamber 16 by actuating (depressing) a first actuator 94 (cap) which moves the pump 32 through a cycle to load fluid into the chamber 16. Once the actuator 94 returns to the default position, fluid is contained in the chamber 16 and ready for delivery. The first actuator 94 may be any suitable actuator, such as a button 95, a rod, a slider, a twist knob, or any other suitable mechanical or electromechanical actuator, without departing from aspects of the present invention. Of course, the fluid may be delivered to chamber 16 during or immediately prior to and during the delivery of the fluid to the eye without departing from all aspects of the invention. The apparatus may also purge the tube 56 of fluid after delivery of fluid to the chamber 16. For example, pump 32 may draw a volume of displacement medium and deliver the displacement medium into tube 56 to displace any fluid in tube 56 into housing 18 prior to delivery.

When the user is ready, the user then actuates the firing button 108 to deliver fluid to the eye. To aim and align the device, the user places the device near the eye and looks through the hole 107 in the shutter 105 and observes the vibrating element 4. A light emitting element 114, such as a light pipe 116, illuminates portions of the device, such as the vibrating element 4, to visually aim and aim the device. Of course, any other suitable aiming/alignment method may be used. Once the device is properly aimed, the firing button 108 is actuated to deliver fluid to the eye. The second actuation may use the same actuator or a different actuator, such as the firing button 108. Although the invention has been described by a two-step actuation process, the two steps may be combined in a single actuation that delivers fluid to chamber 16 and then determines the appropriate time to deliver the fluid, for example by optically distinguishing the eyeball from the eyelid. The device delivers substantially all of the fluid and, after a single actuation and delivery of a single dose or quantity to the eye, the device is ready for storage.

All aspects of the claimed methods and apparatus are applicable to other methods and apparatus, and such claim combinations are expressly incorporated. Furthermore, even if a particular combination, size range, ratio, angle or linear coverage, percentage or any other number of combinations is not previously explicitly claimed, is explicitly incorporated into the claims. For example, the alternate ranges of 75%, 95%, and "all" are used to describe various values that may be used in conjunction with other quantities or in place of one. The terms "first" and "second" are to be interchangeable in the claims, as they are not used as terms of natural order, but merely to distinguish one from another. Furthermore, the claims are open-ended with the terms "having," "carrying," "including," "containing," and "including" (and all other forms of those terms, such as "having") such that "a has B" or "a includes B" means that a includes B, but may also include other elements or process limitations. Finally, the invention has been described with reference to aspects, advantages or operating conditions which are difficult to directly quantify due to their small size and short lead times. Therefore, direct observation and measurement is sometimes not feasible, but qualitative information supports certain claims. For example, it has been observed that when the fluid is ejected, water at the interface of the lip 46 located outside the casing 18 and the vibrating element 4 is sucked into the casing 18, which indicates that air may also be admitted. In addition, even without a dedicated vent, the fluid can be smoothly sprayed.

The present invention has been described with reference to the preferred embodiments, but various modifications can be made without departing from the features and aspects of the present invention. For example, the pump 32 may be a syringe, the housing 18 may be a rigid dome, or the housing 18 may be attached to the vibratory element 4 without departing from aspects of the invention.

Claims

1. An apparatus for delivering a volume of fluid to an eye, comprising:

a housing;

a fluid ejector coupled to the housing, the fluid ejector having a vibratory member with a plurality of openings, the vibratory member having a fluid side and a delivery side, wherein the plurality of openings extend from the fluid side to the delivery side, the fluid ejector ejecting fluid from the fluid side through the plurality of openings to the delivery side when the vibratory member vibrates;

a housing located adjacent to a fluid side of the vibratory element, the housing and vibratory element forming a chamber; and

a pump having an outlet fluidly coupled to the chamber, wherein the pump is configured to draw a discrete dose of liquid from a fluid container into a variable volume cavity and eject the discrete dose from the cavity into the chamber at a pressure of at least 200psi,

wherein the housing comprises a wall having a lip located adjacent the fluid side of the vibratory element, the lip extending around the plurality of openings, the housing and vibratory element together defining the chamber which holds the discrete dose to be dispensed.

2. The apparatus of claim 1, further comprising:

a first actuator operably coupled to the pump, wherein actuation of the first actuator activates the pump to deliver the discrete dose to the chamber.

3. The apparatus of claim 1, further comprising a second actuator operably coupled to the vibrating element, wherein actuation of the second actuator causes the vibrating element to vibrate and eject fluid through the plurality of openings.

4. The device of claim 1, wherein the chamber defined by the housing is substantially empty prior to actuation of the vibratory element and substantially empty after actuation of the vibratory element when the discrete dose is delivered.

5. The device of claim 1, wherein the housing is configured to have no greater than 5% of the discrete dose after a single actuation of the vibratory element.

6. The device of claim 1, wherein the housing is configured to have no greater than 2% of the discrete dose after a single actuation of the vibratory element such that the chamber is substantially empty.

7. The apparatus of claim 1, wherein the housing is configured to have a discrete dose of no greater than 1 microliter as residual fluid upon completion of a single actuation of the vibratory element such that the chamber is substantially empty.

8. The apparatus of claim 1, wherein the chamber defined by the housing has a volume of 10-14 microliters.

9. The apparatus of claim 1, wherein the lip is spaced less than 150 microns from the fluid side of the vibratory element.

10. The apparatus of claim 1, wherein the vibrating element defines a central axis in a direction of a center of the plurality of openings.

11. The apparatus of claim 1, wherein the vibratory element defines a central axis as a center of a spray pattern produced by the plurality of openings.

12. The apparatus of claim 10, wherein the lip is angularly spaced from the fluid side of the vibratory element by less than 250 microns at an angle of at least 270 degrees when viewed along the central axis.

13. The apparatus of claim 10, wherein the housing is spaced apart from the vibratory element by at least 0.014 inches opposite the plurality of openings when viewed along the central axis.

14. The apparatus of claim 1, wherein the housing has an inner surface in contact with the fluid forming the chamber, the inner surface shaped such that at least 75% of the inner surface in contact with the discrete doses is no more than 0.040 inches from a nearest opening of the plurality of openings.

15. The apparatus of claim 1, wherein the housing has an inner surface in contact with the fluid and the inner surface defines the chamber, the inner surface being shaped such that at least 95% of the inner surface is no more than 0.040 inches from a nearest opening of the plurality of openings.

16. The apparatus of claim 1, wherein the housing is shaped such that all fluid in fluid communication with fluid in the chamber is no more than 0.060 inches from a nearest opening of the plurality of openings.

17. The apparatus of claim 1, wherein the housing has an inner surface in contact with the fluid and the inner surface defines the chamber, the inner surface being shaped such that at least 75% of the plurality of openings are at least 0.014 inches from a nearest portion of the inner surface of the housing.

18. The apparatus of claim 1, wherein the housing has an interior surface in contact with the fluid and defining the chamber, the interior surface shaped such that at least 95% of the plurality of openings are at least 0.014 inches from the closest portion of the interior surface of the housing.

19. The apparatus of claim 1, wherein the housing has an inner surface in contact with the fluid, the inner surface being shaped such that the chamber is formed with the entire inner surface no more than 0.040 inches from a nearest opening in the vibrating element.

20. The apparatus of claim 1, wherein the housing has an inner surface shaped such that the chamber is formed such that at least 95% of the inner surface in contact with the fluid is aligned with at least one opening of the plurality of openings.

21. The apparatus of claim 1, wherein the housing has an inner surface shaped such that the chamber is unobstructed by the fluid along at least 75% of the plurality of openings for a distance of at least 0.014 inches measured in a direction along the central axis of the vibratory element.

22. The apparatus of claim 10, wherein the housing has an inner surface shaped such that the chamber is unobstructed by the fluid along at least 95% of the plurality of openings for a distance measured in a direction along the central axis of at least 0.014 inches.

23. The apparatus of claim 1, further comprising a piezoelectric element coupled to the vibrating element, the piezoelectric element being driven at a frequency that varies randomly centered at a drive frequency from 100kHz to 160kHz, wherein the frequency varies at least 20 times during delivery of the fluid.

24. The apparatus of claim 1, further comprising a piezoelectric element coupled to the vibratory element, the piezoelectric element operating at a frequency that varies randomly in a manner centered about a drive frequency range from 100kHz to 160 kHz.

25. The apparatus of claim 1, wherein the vibratory element has a maximum amplitude that is less than an average separation distance between the lip and the vibratory element.

26. The apparatus of claim 1, wherein a maximum amplitude of the vibrating element during vibration and fluid delivery through the opening is 0.5-1.5 microns.

27. The apparatus of claim 1, wherein a maximum amplitude of the vibrating element during vibration and fluid delivery through the opening is 0.8-1.2 microns.

28. The apparatus of claim 1, wherein the plurality of openings in the vibratory element have an average cross-sectional area at the transport side perpendicular to the jet orientation at the openings, the average cross-sectional area defining an effective diameter of the openings at the transport side of the vibratory element, the maximum amplitude of the vibratory element being no greater than 5.0% of the effective diameter of the plurality of openings at the transport side.

29. The apparatus of claim 1, wherein a maximum amplitude of the vibratory element is no greater than 5.0% of a thickness of the vibratory element, the thickness being measured from a fluid side to the delivery side of the vibratory element.

30. The apparatus as claimed in claim 1 wherein the vibrating element has a thickness of 100-180 microns measured from the fluid side to the delivery side.

31. The apparatus of claim 1 wherein the vibratory element has a thickness of 120 and 160 microns measured from the fluid side to the delivery side.

32. The apparatus of claim 10, wherein the lip contacts the vibratory element when viewed along a central axis to retain the fluid in the housing at least 270 degrees around the plurality of openings.

33. The apparatus of claim 1, wherein the lip has no attachment to the vibratory element.

34. The apparatus of claim 10, wherein the lip is made of an elastomeric material having a hardness less than shore 60 a.

35. The apparatus of claim 1, wherein the lip is biased against the vibratory element in the direction of the central axis.

36. The device of claim 1, wherein the lip of the housing exerts a force on the vibratory element of no greater than 3 grams-force measured in a direction of a central axis of the vibratory element.

37. The device of claim 1, wherein the lip of the housing exerts a force on the vibratory element of no greater than 2 grams-force measured in a direction of a central axis of the vibratory element.

38. The apparatus of claim 1, further comprising a mechanism for biasing the lip against the vibratory element.

39. The apparatus of claim 1, wherein the lip portion exerts a spring load on the vibratory element with an average spring constant of no greater than 60 grams force per millimeter for displacements up to 0.050mm in a central axis direction of the housing.

40. The apparatus of claim 1, wherein the lip portion exerts a spring load on the vibrating element with an average spring constant of no greater than 40 grams-force/millimeter for displacements up to 0.050mm in a direction of a central axis of the vibrating element.

41. The apparatus of claim 10, wherein the housing is resilient in the direction of the central axis such that the lip exerts a spring load on the vibratory element.

42. The apparatus of claim 10, wherein the wall of the housing comprises a sidewall having a tapered portion that decreases in size from a large end to a small end, the large end being closer to the vibratory element than the small end and the large end enclosing a larger area than the small end when viewed along the central axis.

43. The apparatus set forth in claim 42 wherein said side wall has a radial extension extending radially inwardly relative to a central axis of said vibratory element at an open end of said housing defined by said lip portion of said housing, said radial extension extending radially inwardly at least 20% of an equivalent radius of the open end of the housing when viewed in cross-section with the central axis located thereon, and said radial extension extending for a total angular extent of at least 270 degrees when viewed along the central axis.

44. The apparatus of claim 43, where the ratio of radial displacement to longitudinal displacement of the radial extension relative to the central axis of the housing is at least 3 to 1 when viewed in cross-section with the central axis located thereon, and the total angular extent over which the radial extension extends is at least 270 degrees when viewed along the central axis.

45. The apparatus of claim 43, wherein the sidewall is tapered and has a ratio of radial displacement to longitudinal displacement from the lip to a proximal end of the chamber formed by the housing of at least 1 to 3 when viewed in cross-section with a central axis located thereon, and a total angular extent to which the sidewall extends of at least 270 degrees when viewed along the central axis.

46. The apparatus of claim 43, where the sidewall has a ratio of radial displacement to longitudinal displacement of at least 2 to 3 when viewed in cross-section with the central axis located thereon, and extends a total of at least 270 degrees when viewed along the central axis.

47. The apparatus of claim 43, where the sidewall has a ratio of radial displacement to longitudinal displacement of at least 1 to 1 when viewed in a cross-section with the central axis located thereon, and the sidewall extends a total of at least 270 degrees when viewed along the central axis.

48. The apparatus of claim 43, wherein the sidewall has a tapered portion that tapers for a radial distance that is at least half of an effective radius of the open end of the housing when viewed in cross-section with a central axis located thereon, and the tapered portion extends a total of at least 270 degrees when viewed along the central axis.

49. The apparatus of claim 43, wherein the sidewall has a tapered portion comprising a frustoconical portion extending at least half of a total longitudinal distance of the tapered portion as measured along a central axis when viewed in a cross-section with the central axis located thereon, and the frustoconical portion extending a total of at least 270 degrees when viewed along the central axis.

50. The apparatus of claim 49, wherein the tapered portion of the sidewall is resilient in a direction of a central axis of the housing such that the lip resiliently contacts the vibratory element.

51. The apparatus of claim 1, wherein the lip and the vibratory element are adjacent to one another to prevent fluid from passing between the lip and the vibratory element along a closed loop around the plurality of openings.

52. The apparatus of claim 10, wherein the lip is spaced apart from the vibratory element by a spacing distance of at least 125 microns around at least 270 degrees of the plurality of openings when viewed along the central axis.

53. The apparatus of claim 1, wherein the housing does not include vent openings to vent air into the housing when fluid is ejected through the opening other than between the lip and the vibratory element and through at least some of the plurality of openings.

54. The apparatus of claim 1, wherein one or more of the plurality of openings permit air to enter the chamber during vibration.

55. The apparatus of claim 1, wherein the lip and the vibratory element allow air to pass between the lip and the vibratory element to vent the housing when fluid is ejected through the plurality of openings.

56. The apparatus of claim 1, further comprising a piezoelectric element coupled to the vibratory element; the vibratory element vibrates for a first time period and a second time period, the first time period and the second time period being separated by a first pause in the driving vibration of the vibratory element.

57. The device of claim 1, further comprising a piezoelectric element that is activated and deactivated by a plurality of pauses in which the piezoelectric element is deactivated, each pause being a continuous time that is at least 2% of the total delivery time, and the total time of the plurality of pauses being at least 6% of the total delivery time.

58. The apparatus of claim 56, wherein,

the vibrating element vibrates for a third time period, the third time period being separated from the second time period by a second pause in the driving vibration; and is

The piezoelectric element operates during a second time period and a third time period to include alternating activation time periods and deactivation time periods,

the inactive time period of the second time period is 2.0% to 2.5% of the second time period,

the inactive time period of the third time period is 2.0% to 2.5% of the third time period,

the sum of the deactivation time periods during the second time period and the third time period is at least 30% of each of the second time period and the third time period, respectively.

59. The apparatus of claim 56, wherein the vibrating element vibrates with a pause in driving vibration of 0.5 to 4.0 ms.

60. The apparatus of claim 56, wherein the vibratory element vibrates with the first and second time periods each being 20-40ms and a total delivery time less than 100 ms.

61. The apparatus according to claim 1, wherein the vibrating element vibrates so that an average ejection velocity at the conveying side of the opening is 2.5 to 12 m/s.

62. The apparatus of claim 1, further comprising:

a fluid container fluidly coupled to the chamber of the housing, the fluid container having a fluid carrying capacity of at least 150 times the volume of the housing; and is provided with

The pump delivers only one dose size.

63. The apparatus of claim 1, wherein the vibratory element defines an encompassing boundary positioned adjacent to a surface of the lip, the encompassing boundary defining an encompassing feeding area bounded by the encompassing boundary, the opening in the vibratory element surrounding and defining a conveying area of the vibratory element.

64. The apparatus of claim 63, wherein the transport region is no greater than 75% of the enclosed feed region.

65. The apparatus of claim 63, wherein the enclosed feed area is at least 30% larger than the transport area.

66. The apparatus of claim 63, wherein the enclosed feed region has an overfeed region that is not coextensive with the transport region when viewed from the direction of the central axis of the vibratory element.

67. Apparatus as claimed in claim 66 wherein the overfeed zone is positioned such that, in use, at least 90% of the overfeed zone is positioned above the geometric centre of the transport zone.

68. The apparatus of claim 66, wherein the overfeed zone is at least 30% of the conveying zone.

69. The apparatus of claim 63, wherein the conveying region of the vibratory element defines a geometric center and has an effective radius, the encompassing feed region of the lip also defining a geometric center and an effective radius.

70. Apparatus as claimed in claim 69, wherein the geometric centre of the enclosed feed region is, in use, above the geometric centre of the transport region.

71. The apparatus of claim 69, wherein the geometric center of the enclosed feed region is offset from the geometric center of the delivery region by a distance of at least 0.3 times an effective radius of the delivery region.

72. The apparatus of claim 1, wherein a chamber formed by the housing is unobstructed to fluid flow such that at least 95% of the fluid in the chamber and any fluid in direct fluid communication with the fluid in the chamber are aligned with at least one of the plurality of openings.

73. The apparatus of claim 1, wherein a chamber formed by the housing is unobstructed to fluid flow such that all fluid in the chamber and any fluid in direct fluid communication with fluid in the chamber are aligned with at least one of the plurality of openings.

74. The apparatus of claim 1, wherein the inner surface of the housing is shaped such that a minimum spacing between at least 75% of the plurality of openings and a nearest portion of the inner surface of the housing is at least 0.014 inches.

75. The apparatus of claim 1, wherein the inner surface of the housing is shaped such that a minimum spacing between at least 95% of the plurality of openings to a nearest portion of the inner surface of the housing is at least 0.014 inches.

76. The apparatus of claim 1, wherein the inner surface of the housing is shaped such that the chamber is formed such that at least 75% of the fluid in direct fluid communication with the fluid in the chamber is no more than 0.060 inches from the nearest opening in the vibratory element.

77. The apparatus of claim 1, wherein the inner surface of the housing is shaped such that the chamber is formed such that at least 95% of the fluid in direct fluid communication with the fluid in the chamber is no more than 0.040 inches from the nearest opening in the vibrating element.

78. The apparatus of claim 1, wherein the inner surface of the housing is shaped such that the chamber is formed such that all fluid in direct fluid communication with fluid in the chamber is no more than 0.060 inches from a nearest opening in a vibratory element.

79. The apparatus of claim 66, wherein the overfeed region extends radially outward at least 270 degrees of the enclosed feed region by at least 0.3 times an effective radius of the enclosed feed region when viewed relative to a central axis of the vibratory element.

80. The apparatus of claim 66, wherein the overfeed region extends completely around the enclosed feed region at least 0.3 times an effective radius of the enclosed feed region.

81. The apparatus of claim 66, wherein the overfeed region is defined by a tapered portion of a sidewall of the housing when viewed along a central axis of the vibratory element, the tapered portion of the sidewall having a large end positioned closer to the vibratory element.

82. The apparatus of claim 1, wherein the housing has a side wall and a main inlet that receives fluid, the housing further having first and second inlets through which fluid enters the chamber, the first and second inlets opening into the chamber and both being oriented to direct fluid to the side wall of the housing before fluid is directed to the plurality of openings.

83. The apparatus of claim 82, wherein the first and second inlets direct at least 90% of the fluid to the enclosure, and less than 10% of the fluid is directed to the vibratory element before the fluid is directed to the enclosure.

84. The apparatus of claim 1, further comprising:

a tube having an inner lumen; and is

The housing has a primary inlet fluidly coupled to the lumen in the tube, the primary inlet oriented to direct fluid onto an inner wall of the housing, the inner wall forming a diverter chamber having at least two separate inlets to the chamber, and each inlet to a chamber directs fluid to a sidewall of the housing.

85. The apparatus of claim 84, wherein the diverter chamber has a third inlet and a fourth inlet corresponding to a third flow path and a fourth flow path, respectively.

86. The apparatus of claim 1, wherein

The vibrating element has a central axis defined by a central direction of the spray pattern emitted by the plurality of openings; and is

The housing has a main inlet directing flow in a direction within 30 degrees of a central axis, the housing has a sidewall and a diverter chamber fluidly coupled to the main inlet to receive fluid, the diverter chamber shaped to redirect and divert fluid flow from the main inlet to one or both of a first inlet and a second inlet oriented at 60-90 degrees from the central axis, the first inlet and the second inlet directing fluid to the sidewall of the housing before the fluid is directed to the plurality of openings.

87. The apparatus of claim 1, wherein the housing has a first inlet, a second inlet, a third inlet, and a fourth inlet, the first, second, third, and fourth inlets each oriented at a sidewall of the housing and oriented at 60-120 degrees from an adjacent inlet when viewed along a central axis of the housing.

88. The apparatus of claim 1, wherein the housing has a sidewall and a diverter chamber that receives fluid from the main inlet of the tube, the diverter chamber being formed by a wall extending from one side of the sidewall to an opposite side of the sidewall when viewed along a central axis defined by a lip of the housing.

89. The apparatus of claim 1, wherein the housing has an integrally formed structure that defines at least the chamber.

90. The apparatus of claim 1, further comprising:

a tube having an internal cavity with a volume of less than 2 microliters;

a valve having an open position that allows fluid flow through the lumen and a closed position that prevents fluid flow through the lumen; and is

The housing has a primary inlet fluidly coupled to a lumen in the tube.

91. The device of claim 1, further comprising a tube having an inner lumen with a volume of less than 2 microliters and wherein,

the pump having an open position that allows fluid flow through the lumen and a closed position that prevents fluid flow through the lumen; and is

The housing has a primary inlet fluidly coupled to the lumen in the tube.

92. The apparatus of claim 1, wherein the pump has a first portion and a second portion movably coupled to one another to change a size of the variable-volume chamber, wherein the first portion and the second portion are configured to reciprocate between a storage position, a partial stroke position, and a full forward stroke position,

wherein when the first and second portions are moved from the storage position towards the partial stroke position, the first portion moves away from the second portion and the cavity increases in size to aspirate the discrete dose,

wherein when the first and second portions are in the fully forward stroke position, the first and second portions are maximally displaced from each other, the cavity has a maximum size and is aligned with an internal cavity into the chamber, and

wherein when the first and second portions are moved from the fully forward stroke position towards the storage position, the first and second portions move towards each other and the cavity decreases in size to eject the discrete dose.

93. The apparatus of claim 92, wherein a first portion of the pump has a first extension and a second portion of the pump has a second extension, wherein the first extension extends toward and interlocks with the second extension, the first portion driving the second portion throughout a cycle.

94. The apparatus of claim 92, further comprising: a first actuator operably coupled to the first portion, the actuator driving the first portion through a forward stroke and also loading a pump return spring during the forward stroke, the loaded pump return spring moving the first portion of the pump and the second portion of the pump from a fully forward stroke position back to a storage position.

95. The apparatus of claim 92, wherein the fluid is drawn into the variable-volume chamber formed between the first and second portions during a forward stroke of the first portion.

96. The apparatus of claim 92, wherein fluid is drawn into the variable-volume chamber formed between the first and second portions during a forward stroke, the variable-volume chamber changing in size as the first and second portions move toward and away from each other.

97. The device of claim 92 wherein the variable volume chamber of the pump contains a volume of 7-12 microliters delivered to the housing.

98. The apparatus of claim 1, further comprising:

a tube having an inner lumen in fluid connection with the chamber; and

a valve that opens to allow fluid flow through the lumen and closes to prevent fluid flow through the lumen, the total downstream volume being defined by the total volume including at least the lumen and a chamber tube located downstream of the valve, the volume of fluid delivered into the chamber can be 40% -70% of the total downstream volume.

99. The apparatus of claim 1, further comprising an air replenishment chamber connected to the pump, the pump forcing air from the air replenishment chamber into the fluid container during each cycle.

100. The apparatus of claim 92, further comprising an air replenishment chamber connected to a pump, wherein the pump draws air into the air replenishment chamber during a full forward stroke of the first portion and forces air into the fluid container during a return stroke of the first portion back to a storage position.

101. The apparatus of claim 1, further comprising:

a shutter having a hole, the shutter being movable from a storage position covering the plurality of openings when viewed along a central axis of the hole through the shutter to a delivery position where the plurality of openings are exposed when viewed along the central axis of the hole through the shutter; and

a ram spring coupled to the ram, the ram spring loaded when the first actuator moves the first portion of the pump during the forward stroke, the ram spring coupled to the ram, the ram moved from the delivery position back to the storage position by the ram spring.

102. The apparatus of claim 1, further comprising a control system mounted on the housing, the control system coupled to a first actuator and operably coupled to the vibratory element to control the vibratory element.

103. The apparatus of claim 1, wherein the housing comprises a first housing portion and a second housing portion, the first housing portion removably coupled to the second housing portion; the control system is mounted on the first housing section.

104. The apparatus of claim 103, wherein the housing is mounted to a second housing portion; and is

The vibratory element is mounted to the second housing portion.

105. The apparatus of claim 103, wherein the fluid container is connected to the second housing portion, the fluid container being mounted to the second housing portion so as to be non-replaceable such that the second housing portion is discarded with the fluid container.

106. The apparatus of claim 1, further comprising:

a tube having an inner lumen, the inner lumen being in fluid connection with the chamber;

a valve positioned in communication with the lumen, the valve opening to allow fluid flow through the lumen and closing to prevent fluid flow through the lumen.

107. The apparatus of claim 106, wherein a total downstream volume is defined by a total downstream volume downstream of the valve and including at least the lumen and the chamber, a volume of fluid delivered to the chamber through the lumen in the tube being between 40% and 70% of the total downstream volume.

108. The apparatus of claim 1, further comprising a tube having a lumen in fluid connection with the chamber, wherein the pump is positioned in communication with the lumen, the pump being open to allow fluid flow through the lumen and closed to prevent fluid flow through the lumen.

109. The apparatus of claim 1, wherein the pump delivers the discrete dose to the chamber at a speed of at least 1.0 m/s.

110. The apparatus of claim 1, wherein the housing includes a main inlet fluidly coupled to a flow splitting chamber having a cup-shaped wall with a concave side facing away from the vibratory element.

111. The apparatus of claim 110, wherein the cup-shaped wall has first and second inlets formed therein, the cup-shaped wall extending radially outward from a central axis of the housing by at least 25% of an effective radius defined by the lip.

112. The apparatus of claim 111, wherein the first inlet and the second inlet each have a radial dimension and a longitudinal dimension relative to a central axis of the housing, a ratio of the radial dimension to the longitudinal dimension being 0.5 to 1.5.

113. The apparatus of claim 111, wherein the first and second inlets each expose some of the primary inlets when viewed in a direction along a central axis of the housing.

114. The apparatus of claim 1, wherein the lip has a degree of freedom relative to the vibratory element in a direction of a central axis of the vibratory element.

115. The apparatus of claim 1, wherein the lip has a PTFE coating adjacent the vibrating element to reduce friction therebetween, the coating extending at least 270 degrees around the lip when viewed along the central axis.

116. The apparatus of claim 1, wherein the vibrating element has a PTFE coating adjacent the lip to reduce friction therebetween, the coating extending around at least 270 degrees when viewed along a central axis.

117. The apparatus of claim 1, wherein the inner surface of the housing is hydrophobic over at least 70% of the inner surface in contact with the fluid.

118. The apparatus of claim 1, further comprising: a wall opening extending through the wall to expose the chamber.

119. The apparatus according to claim 118, wherein said wall opening forms a gap in said lip.

120. The apparatus according to claim 118 wherein said wall opening has a longitudinal dimension measured from said lip in the direction of a central axis and a radial dimension measured in a radial direction relative to said central axis, said housing having an inner wall having a side facing the opening in the vibrating element, said side facing the opening in the vibrating element being spaced from said opening.

121. The apparatus according to claim 118, wherein said wall opening is located along a frustoconical portion, said wall opening extending proximally from said lip for at least 80% of a length of said frustoconical portion.

122. The apparatus according to claim 120 wherein a longitudinal dimension of said wall opening is at least 80% of a spacing between said vibrating element and a side of said housing facing said opening.

123. The apparatus of claim 120, wherein a radial dimension of the wall opening is no greater than 10% of an equivalent circumference of the lip.

124. The apparatus according to claim 120 wherein a radial dimension of said wall opening is no greater than 5% of an equivalent circumference of said lip.

125. The apparatus according to claim 118, wherein the wall opening extends proximally from the lip, the wall opening tapering in circumferential dimension as the wall opening extends proximally from the lip.

126. The apparatus of claim 125, wherein the wall opening is tapered such that the tapered shape of the wall opening is oriented in a direction of the inlet to the chamber when viewed along a central axis.

127. The apparatus of claim 118, wherein the wall opening vents the enclosure by allowing air to enter the chamber when fluid is ejected, the wall opening being sufficiently small to prevent the passage of the fluid.

128. The apparatus of claim 1, wherein a thickness of a wall of the housing surrounding the chamber is 0.003 to 0.007 inches.

129. The apparatus of claim 126, wherein the wall opening is tapered such that the tapered shape of the wall opening is oriented in a direction to at least two separate inlets to the chamber when viewed along the central axis.

130. A fluid handling device for use with a device for delivering fluid to an eye, comprising:

a housing comprising a side wall having a lip surrounding and defining an open end of the housing, the lip being positioned adjacent the vibratory element in use, the housing having an inner surface which together with the open end defines a chamber when the lip is positioned adjacent the vibratory element in use, the open end being positioned adjacent the vibratory element to surround a plurality of openings in the vibratory element through which fluid in the chamber is dispensed when the vibratory element vibrates, the vibratory element having a fluid side and a transport side, the plurality of openings extending from the fluid side to the transport side, the vibratory element ejecting fluid from the fluid side through the plurality of openings to the transport side when the vibratory element vibrates, the lip extending around the plurality of openings in use; and

a pump having an outlet fluidly coupled to the chamber,

wherein the pump is configured to draw a discrete dose of liquid from a fluid container into a variable volume cavity of the pump and eject the discrete dose from the cavity into the chamber at a pressure of at least 200 psi.

131. The apparatus of claim 130, further comprising: a tube having an inner lumen fluidly coupled to the chamber of the housing to deliver fluid to the chamber through the inner lumen.

132. The apparatus according to claim 130, wherein the chamber holds a single application of fluid to the eye, wherein in use the chamber is substantially evacuated and the chamber holds less than 14 microliters of fluid in a single actuation of the vibrating element.

133. The apparatus of claim 130, wherein the chamber formed by the housing has a volume of 10-14 microliters.

134. The apparatus of claim 130, wherein the chamber formed between the housing and the vibrating element is filled with 70-95% of a volume of fluid.

135. The apparatus of claim 130, wherein the chamber holds a fluid volume of 7-12 microliters in use.

136. An apparatus as claimed in claim 130 wherein the lip is spaced from the fluid side of the vibrating element by an average spacing distance of less than 250 microns in use.

137. The apparatus of claim 130, wherein the lip is spaced less than 250 microns from the fluid side of the vibrating element about at least 270 degrees when viewed along a central axis.

138. The apparatus of claim 130, wherein the housing is spaced at least 0.014 inches from the vibrating element opposite the plurality of openings when viewed along the central axis.

139. The apparatus of claim 130, wherein the vibrating element has a maximum amplitude during vibration that is less than an average separation distance between a surface of the lip and the vibrating element.

140. The apparatus of claim 130, further comprising a piezoelectric element coupled to the vibrating element.

141. The apparatus of claim 130, wherein a maximum amplitude of the vibrating element during transport and vibration of the fluid through the opening is 0.5-1.5 microns.

142. The apparatus of claim 130, wherein a maximum amplitude of the vibrating element during transport and vibration of the fluid through the opening is between 0.8-1.2 microns.

143. The apparatus of claim 130, wherein the plurality of openings have a cross-sectional area perpendicular to a jetting direction of the openings at the delivery side, the cross-sectional area defining an effective diameter of the openings at the delivery side, a maximum amplitude of the vibrating element being no greater than 5.0% of the effective diameter of the plurality of openings at the delivery side.

144. The apparatus of claim 130, wherein the maximum amplitude of the vibrating element is no greater than 3.0% of a thickness of the vibrating element, the thickness being measured from a fluid side to a delivery side of the vibrating element.

145. The apparatus of claim 130 wherein the vibration member has a thickness of 100 and 180 microns measured from the fluid side to the delivery side.

146. The apparatus of claim 130 wherein the vibration member has a thickness of 120-160 microns measured from the fluid side to the delivery side.

147. The apparatus of claim 130, wherein the lip is in contact with the vibrating element to retain the fluid in the housing.

148. The apparatus of claim 130, wherein the lip is free of attachment to the vibration element.

149. The apparatus according to claim 130, wherein the lip is made of an elastic material.

150. The apparatus of claim 130, wherein the lip is biased against the vibrating element to retain the fluid within the chamber.

151. The apparatus of claim 130, wherein the lip is biased against the vibrating element with a force of less than 3 grams force measured along a central axis.

152. The device of claim 130, wherein the lip exerts a force on the vibrating element of less than 2 grams force when the lip is in contact with the vibrating element in the direction of the central axis.

153. The apparatus of claim 130, wherein the lip applies a spring load to the vibratory element with an average spring constant of no greater than 60 grams-force/millimeter for displacements up to 0.005 inches in the direction of the central axis.

154. The device of claim 130, wherein the housing has sidewalls that are resilient and apply a spring load to the vibratory element in the direction of the central axis.

155. The apparatus of claim 130, wherein the vibrating element defines a central axis in a central direction of the plurality of openings and is oriented in a jetting direction.

156. The apparatus of claim 130, wherein the vibrating element defines a central axis at a center of a spray pattern produced by the plurality of openings.

157. The apparatus of claim 130, wherein the open end of the housing has a geometric center, the open end defining a central axis extending through the geometric center perpendicular to the area encompassed by the lip.

158. The device of claim 130, wherein the housing has sidewalls that decrease in size from a large end to a small end, the large end being positioned closer to the vibrating element and surrounding a larger area than the small end.

159. The apparatus of claim 158, wherein the sidewall of the housing comprises a frustoconical portion and a radial extension extending radially inward from a small end of the frustoconical portion.

160. The apparatus of claim 158, wherein the sidewall includes a radial extension that extends radially inward relative to a central axis of the opening defined by the lip, the radial extension extending radially inward at least 20% of an equivalent radius of an open end of the housing defined by the lip when viewed in cross-section with the central axis located thereon, and the radial extension extending a total of at least 270 degrees when viewed along the central axis.

161. The apparatus of claim 160, wherein the ratio of radial displacement to longitudinal displacement of the radial extension relative to a central axis defined by the open end of the housing is at least 3 to 1 when viewed in cross-section with the central axis located thereon, and the radial extensions collectively extend at least 270 degrees when viewed along the central axis.

162. The apparatus of claim 158, wherein the sidewall is tapered and has a ratio of radial displacement to longitudinal displacement of at least 1 to 3 when viewed in cross-section of the housing on which the central axis lies, and the sidewall extends a total of at least 270 degrees when viewed along the central axis.

163. The apparatus of claim 158, wherein the sidewall has a ratio of radial displacement to longitudinal displacement of at least 2 to 3 when viewed in cross-section with the central axis of the housing located thereon, and the sidewall extends a total of at least 270 degrees when viewed along the central axis.

164. The apparatus of claim 158, wherein the sidewall has a ratio of radial displacement to longitudinal displacement of at least 1 to 1 when viewed in a cross-section on which the central axis of the housing lies, and the sidewall extends a total of at least 270 degrees when viewed along the central axis.

165. The apparatus of claim 158, wherein the sidewall has a first frustoconical portion.

166. The apparatus of claim 158, wherein the thickness of the sidewall along the tapered portion of the sidewall is less than 0.005 inches.

167. The apparatus of claim 158, wherein the sidewall has a ratio of radial displacement to an effective radius of an area encompassed by the lip portion of at least 1 to 8 when viewed in a cross-sectional plane on which a central axis of the housing lies, and the sidewall extends a total of at least 270 degrees when viewed in a direction of the central axis.

168. The apparatus of claim 130, wherein the lip has a surface positioned adjacent to the vibrating element, the surface of the lip being in contact with the vibrating element and having a degree of freedom in a direction of the central axis relative to the vibrating element.

169. The apparatus of claim 130, wherein

The vibrating element defines a central axis at a geometric center of the plurality of openings, which is oriented in a jetting direction of the openings; and is provided with

The lip has a surface spaced from the vibratory element by less than 125 microns around at least 270 degrees of the plurality of openings when viewed along the central axis.

170. The apparatus of claim 130, wherein the lip is spaced apart from the vibratory element by a spacing distance of at least 125 microns around at least 270 degrees of the plurality of openings when viewed along the central axis.

171. The apparatus of claim 130, wherein the housing does not include vent openings to vent air into the housing when fluid is ejected through the opening other than between the lip and the vibrating element and through at least some of the plurality of openings in the vibrating element.

172. The apparatus of claim 130, wherein the lip and the vibrating element allow air to be drawn into some of the plurality of openings during vibration of the vibrating element.

173. The apparatus of claim 130, wherein the lip and the vibratory element aerate the enclosure when fluid is ejected through the plurality of openings.

174. The apparatus of claim 130, wherein the vibratory element defines an enclosing boundary positioned adjacent a surface of the lip, the enclosing boundary preventing fluid from escaping therebetween with the surface of the lip, the enclosing boundary defining an enclosing feed region, the enclosing feed region being a region bounded by the enclosing boundary, the opening in the vibratory element enclosing a delivery region of the plurality of openings in the vibratory element.

175. The apparatus of claim 174, wherein a delivery area of the vibratory element is no greater than 75% of the enclosed feed area.

176. The apparatus of claim 174, wherein the enclosed feed area is at least 30% larger than the delivery area.

177. The apparatus of claim 174, wherein the enclosed feed region defines an overfeed region that is not coextensive with the delivery region when viewed in the direction of the central axis.

178. The apparatus of claim 177, wherein in use, at least 90% of the overfeed zone is located above the geometric center of the transport zone.

179. The apparatus of claim 177, wherein the size of the overfeed zone is at least 30% of the conveying zone.

180. The apparatus of claim 174, wherein the delivery region of the vibratory element defines a geometric center and an effective radius, the encompassing feed region of the surface of the lip also defining a geometric center and an effective radius.

181. The apparatus claimed in claim 180 and wherein in use the geometric centre of said enclosed feed zone is above the geometric centre of said delivery zone.

182. The apparatus of claim 180, wherein a geometric center of the enclosed feed region is offset from a geometric center of the delivery region by at least 0.3 times an effective radius of the delivery region.

183. The apparatus of claim 130, wherein the chamber formed between the housing and the vibrating element defines a geometric center, the geometric center of the fluid within the chamber being positioned no greater than 0.015 inches from the vibrating element as measured in a direction along the central axis, the vibrating to evacuate the fluid within the chamber.

184. The apparatus of claim 130, wherein a chamber formed by the housing is unobstructed to fluid flow such that at least 95% of fluid in the chamber is aligned with a nearest opening in the vibratory element.

185. The apparatus of claim 130, wherein a chamber formed by the housing is unobstructed to fluid flow such that all fluid in the chamber and fluid in communication with fluid in the chamber are aligned with a nearest opening in a vibrating element.

186. The apparatus of claim 130, wherein the housing has an inner surface shaped such that a minimum separation between at least 75% of the plurality of openings and a nearest portion of the inner surface of the housing is at least 0.014 inches.

187. The apparatus of claim 130, wherein the housing has an inner surface shaped such that a minimum separation between at least 95% of the plurality of openings and a nearest portion of the inner surface of the housing is at least 0.014 inches.

188. The apparatus of claim 130, wherein an inner surface of the housing is shaped such that the chamber is formed such that at least 75% of the fluid in direct fluid communication with the fluid in the chamber is no more than 0.040 inches from a nearest opening in the vibrating element.

189. The apparatus of claim 130, wherein an inner surface of the housing is shaped such that the chamber is formed such that at least 95% of fluid in direct fluid communication with fluid in the chamber is no more than 0.060 inches from a nearest opening in the vibrating element.

190. The apparatus of claim 130, wherein an inner surface of the housing is shaped such that the chamber is formed such that all fluid in direct fluid communication with fluid in the chamber is no more than 0.060 inches from a nearest opening in the vibrating element.

191. The apparatus of claim 177, wherein the overfeed region extends outwardly from the enclosed feed region along at least 270 degrees of the enclosed feed region by at least 0.3 times an effective radius of the enclosed feed region when viewed along the central axis.

192. The apparatus of claim 177, wherein the overfeed region extends completely around the enclosed feed region.

193. The apparatus of claim 177, wherein the overfeed region is defined by a tapered portion of a sidewall of the housing when viewed along the central axis.

194. The apparatus of claim 130, wherein the housing has a primary inlet that receives the fluid, the primary inlet directing the fluid to a first inlet and a second inlet, the fluid entering the chamber through the first inlet and the second inlet, the first inlet directing the fluid to the first surface of the housing before the fluid is directed to the plurality of openings in the vibratory element.

195. The apparatus of claim 130, wherein the housing has a main inlet through which a volume of fluid is introduced, the housing further having at least first and second inlets to the chamber, the first and second inlets both being oriented to direct fluid to a surface of the housing before the fluid is directed to the plurality of openings in the vibratory element.

196. The apparatus of claim 130, wherein at least a first inlet and a second inlet direct at least 90% of the fluid to the enclosure such that less than 10% of the fluid is directed to the vibratory element before being directed to the enclosure.

197. The apparatus of claim 130, wherein the housing has a primary inlet that directs fluid to a first surface of the housing that divides fluid flow into at least three separate inlets that respectively direct fluid at sidewalls of the housing as it enters the chamber.

198. The apparatus of claim 130, wherein the housing has a diverter chamber that receives fluid from a main inlet of the housing, the diverter chamber having first and second fluid inlets that divide the fluid flow into a first flow along a first flow path and a second flow along a second flow path.

199. The apparatus of claim 198, wherein the diverter chamber has third and fourth inlets corresponding to the third and fourth flow paths, respectively, both of which direct fluid to the side wall of the housing before the fluid is directed to the opening.

200. The apparatus of claim 130, wherein the housing has a main inlet that directs fluid flow in a direction that is within 30 degrees of a central axis of the housing, the housing having a sidewall and a diverter chamber fluidly coupled to the main inlet to receive the fluid, the diverter chamber redirecting fluid flow from the main inlet into at least first and second inlets oriented 60-90 degrees from the central axis, the first and second inlets directing fluid to the sidewall of the housing before being directed to the plurality of openings.

201. The apparatus of claim 200, wherein the housing has third and fourth inlets that receive fluid from the diverter chamber, the third and fourth inlets to the chamber being oriented at a sidewall of the housing.

202. The apparatus of claim 130, wherein the housing has a first inlet, a second inlet, a third inlet, and a fourth inlet, the first, second, third, and fourth inlets each oriented at a sidewall of the housing and oriented at 60-120 degrees from an adjacent inlet when viewed along a central axis.

203. The apparatus of claim 130, wherein the housing comprises an inner wall extending from a first portion of the sidewall to an opposite portion of the sidewall, the inner wall extending substantially perpendicular to the central axis, the inner wall extending radially outward from the central axis a distance of at least 20% of an effective radius of an area encompassed by the lip, the inner wall positioned 0.014 to 0.030 inches from the vibratory element as measured along the central axis.

204. The apparatus of claim 130, wherein the inner wall of the housing and the proximal end of the side wall of the housing together form a diversion chamber having four inlets to the chamber, each inlet directing the fluid to the side wall.

205. The apparatus of claim 204, wherein the four inlets formed by the inner walls of the diversion chamber are oriented 60-90 degrees from the central axis.

206. The apparatus according to claim 130 wherein the housing is an integrally formed structure defining the chamber with an area of the open end surrounded by the lip.

207. The apparatus of claim 130, wherein the housing comprises a main inlet fluidly coupled to a flow-splitting chamber having a cup-shaped wall with a concave side facing away from the vibrating element.

208. The apparatus of claim 207, wherein the cup-shaped wall has first and second inlets formed therein, the cup-shaped wall extending radially outward from a central axis of the housing at least 25% of an effective radius defined by the lip.

209. The apparatus of claim 208, wherein the first inlet and the second inlet each have a radial dimension and a longitudinal dimension relative to the central axis, the ratio of the radial dimension to the longitudinal dimension being 0.5 to 1.5.

210. The apparatus of claim 208, wherein the first and second inlets each expose some of the primary inlets when viewed in a direction along a central axis of the housing.

211. The apparatus of claim 130, wherein the lip has a degree of freedom with respect to the vibrating element in a direction of a central axis of the vibrating element.

212. The apparatus of claim 130, further comprising:

a piezoelectric element coupled to the vibration element;

the vibratory element vibrates for a first time period and a second time period, the first time period and the second time period being separated by a first pause in the driving vibration of the vibratory element.

213. The apparatus of claim 130, further comprising: a piezoelectric element that is activated and deactivated in a plurality of pauses in which the piezoelectric element is deactivated, each pause being a continuous time, the continuous time being at least 2% of a total delivery time, and a total time of the plurality of pauses being at least 6% of the total delivery time.

214. The apparatus of claim 130, further comprising:

a piezoelectric element coupled to the vibration element;

after a second time period, vibrating the element to drive a second pause in vibration followed by a third time period;

the piezoelectric element operates during a second time period and a third time period to include alternating activation periods and deactivation periods, each deactivation period being 2.0% to 2.5% of each of the second time period and the third time period, the sum of the deactivation periods during the second time period and the third time period being at least 30% of each of the second time period and the third time period, respectively.

215. The apparatus of claim 130, wherein the vibrating element vibrates with a pause in driving vibration of 0.5 to 4.0 ms.

216. The apparatus of claim 130, wherein the vibratory element vibrates with the first time period and the second time period each being 20-40ms and a total delivery time less than 100 ms.

217. The apparatus of claim 130, wherein the lip has a PTFE coating adjacent the vibrating element to reduce friction therebetween, the coating extending around at least 270 degrees when viewed along the central axis.

218. The apparatus of claim 130, wherein the vibrating element has a PTFE coating adjacent the lip to reduce friction therebetween, the coating extending around at least 270 degrees when viewed along the central axis.

219. The apparatus of claim 130, wherein the inner surface of the housing is hydrophobic over at least 70% of the inner surface in contact with the fluid.

220. The apparatus of claim 130, further comprising: a wall opening extending through the sidewall to expose the chamber.

221. The apparatus according to claim 220, wherein said wall opening forms a gap in said lip.

222. The apparatus of claim 220, wherein the wall opening has a longitudinal dimension measured from the lip in a direction of a central axis and a radial dimension measured in a radial direction relative to the central axis, the housing having an inner wall with a side facing the opening in the vibrating element, the side facing the opening in the vibrating element being spaced apart from the opening.

223. The apparatus of claim 220, wherein the sidewall includes a frustoconical portion, the wall opening extending proximally from the lip at least 80% of a length of the frustoconical portion.

224. The apparatus of claim 222, wherein a longitudinal dimension of the wall opening is at least 80% of a spacing between the vibrating element and the side of the housing facing the opening.

225. The apparatus of claim 222, wherein a radial dimension of the wall opening is no greater than 10% of an equivalent circumference of the lip.

226. The apparatus of claim 222, wherein a radial dimension of the wall opening is no greater than 5% of an equivalent circumference of the lip.

227. The apparatus of claim 220, wherein the wall opening extends proximally from the lip, a circumferential dimension of the wall opening gradually decreasing as the wall opening extends proximally from the lip.

228. The apparatus of claim 220, wherein the wall opening is tapered such that the tapered shape of the wall opening is oriented in a direction of the inlet to the chamber when viewed along a central axis.

229. The apparatus of claim 220, wherein the wall opening vents the housing by allowing air to enter the chamber upon fluid ejection.

230. The apparatus of claim 130, wherein a thickness of a sidewall of the housing surrounding the chamber is 0.003 to 0.007 inches.